New York is a long long way from the Island, or Islands where the Sesame street monsters and their colleagues must have originally evolved.

Was it one Island?  Or two?  Or three?   We can't say for sure.   It's highly likely that the Sesame Monsters and the Big Birds are from the same Island and probably evolved at the same time.  They both seem to be creatures of similar backgrounds, probably temperate or tropical rain forest types.   Certainly we know that Lemurs and Giant Birds co-evolved in Madagascar, so there's proof that they do get along.

And they would both need similar long periods of isolation on the order of fifty million years or better.   Simply put, if the mainland life was able to get onto the island, then predators and competitors would have prevented giant birds or advanced sloth-like prosimians from ever evolving.

But this poses a problem, because in evolutionary terms, Snuffleupagas is a johnny come lately.  His ancestral species, the Southern Mammoth only goes back some four million years and died off about a million years ago.  So the Snuffleupagas emerges far more recently.   If it's the same Island, how does he get there.   And what does it mean?

The key lies in the Ice Ages starting about three million years ago.   The Ice Ages soaked up lots of water and locked it up as ice.  Sea levels dropped dramatically.   As a result, Australia and New Guineau were connected as a single land mass.   Most of the big islands of Indonesia were connected to Indochina and the Asian mainland.   Sri Lanka was part of India.   The British Isles were a part of a greater European land mass.  Land bridges joined Asia to North America.

And of course, there's tectonic plates, moving against each other.  Pushing up crust or letting it sink down, even creating its own temporary land bridges in the form of chains of islands or mountainous ridges.

So, on our hypothetical Sesame Island we can postulate a long period of isolation from the mainland, perhaps dating all the way back to the end of the age of dinosaurs.

The inhabitants of this Island cannot walk there.   They either fly there, as the birds did.  Or they're castaways, small prosimians clinging to trees washed away by floods or tsunamis.   The Lemurs of Madagascar and the New World Monkeys of South America both arrived on their shores as castaways.

Indeed, we can speculate about a few of the other animals that would have wound up populating Sesame.   Lizards and turtles, as we've seen with Indian Ocean tortoises and Galapagos tortoises and Iguanas.   Perhaps a few other tree clingers, small insectivores or leaf eaters.  By water, some of the better swimmers, crocodiles and otters perhaps.

The period of initial colonization, as we've noted, would have been about forty to fifty million years ago.  Our yardstick is the period when the prosimians were at their height.   After that, they were in decline and monkeys and later apes were taking over.

To produce the giant birds and advanced prosimians, our Island would probably have to have been about the same ballpark as Sri Lanka, give or take.  Say about 25,000 to 15,000 square kilometers.

And its probably situated in the tropics, probably in the rain corridor.  Largely because our reconstruction of the Sesame Monsters puts them as rain forest creatures, and our analysis of the big birds also places them as swampy creatures.   It's wet and humid, though there may be a cold season, most likely from Antarctic currents.

Its likely that Sesame Island experiences a marvelous adaptive radiation.  After all, just about every niche is vacant, and there are a lot of niches.   New Zealand did not produce a single species of Moa, but over a dozen, ranging in size from giants to Kiwis and occupying a range of habitats.  Madagascar flowered, producing several types of flightless birds, and an assortment of lemurs ranging from monkey-like creatures to giants with the size and lifestyle of apes and sloths.

The Big Birds and Sesame Monsters that we see are both specialized creatures.  Its likely that they had cousins, ground dwelling ape-like creatures, and grasslands roaming giant birds, with midgets, behemoths, oddballs of every sort.  It must have been a strange wonderland, with barely a predator, if any, to be found.

We can't identify the ultimate ancestors of the Big Birds, so this gives us no clue as to geography.  But we can say with reasonable confidence that the Lorisidae which gave rise to the Sesame Monsters were indigenous to Africa and the southern reaches of Asia.

This suggests that our hypothetical island is probably in the Indian Ocean, or at the most westerly, its probably in the South China sea and the oriental areas of the Pacific.  There's a lot of Islands in that area.   We might also consider the Southern reaches of the Atlantic near Africa.

At the same time, we can easily rule out the North Pacific, the open South Pacific, the Southern reaches of the Indian Ocean, the North Atlantic, or anywhere near the Americas, Australia, Europe or Northern Asia.

If we assume, Snuffleupagas is from the same Island, and is derived from the Southern Mammoth, we can mostly rule out African waters.   Which puts us in either the Indian or Pacific oceans near Southern Asia and India.

We can also speculate that it is far enough from the mainland that there aren't a lot of biological immigrants.  The birds and loridae are not overwhelmed by new competitors, allowing them to evolve where they want to go.   But on the other hand, it has to be close enough that dropping sea levels during the ice age, or perhaps geological processes, allow a temporary land bridge to form.   So, perhaps a few dozen miles from the mainland, perhaps a couple of hundred.   No more than that.   That land bridge changes everything.

We can assume that if the mammoths crossed the land bridge, then it was principally a grasslands area.  That stands to reason, the elevation is low and flat, drainage is probably rapid, the area's only above the water for a comparatively short time.   The Mammoths are grasslands creatures, so its likely that the flora and fauna of the land bridge was suitable to them.   So, probably not mountain or rugged country, and probably not thick rain forest either.

But here's the problem.   If Mammoths can get across the land bridge, then other animals can too.  Predators like wolves or lions, competitors like buffalo or antelope.   The sheltered flora and fauna of Sesame Island are about to meat the ferocious competitors of the mainland.

The result is mass extinction.   The outside mainland animals have been competing and evolving under harsher conditions in a much larger land area.  Larger land masses mean greater populations, which in turn means greater mutation rates and more rapid change.  It also means more competitors driving those changes.

Historically, the joining of two separated land masses has been disastrous for the animals of one of them.   The best example is the joining of South America to North America, which itself was already connected to Eurasia.  Before the merger, South America had produced a dizzying assortment of strange life forms, Sloths the size of elephants, Glyptodonts armoured like tanks, marsupial saber tooth tigers, giant predator birds, lions and wolves, imitations of elephants and horses, condors with 25 foot wingspans, giraffe like creatures with elephant like trunks.   When the two continents joined, 90% of South America's species were wiped out.

On a less dramatic scale, its happened many times.   The prior joining of North America to Asia resulted in extinction for a whole range of North American species.   Human discoveries of Australia, Hawaii, New Zealand and Madagascar resulted in the extinctions of much of the slower megafauna of each of these places.   Pity the poor Dodo, he didn't survive meeting us.

So Sesame Island's remarkable diversity of species, the cousins to the Big Birds and the Sesame Monsters were probably all wiped out.

So why did the Sesame Monsters and the Big Birds survive?  What was their secret?

I think that their survival gives us another clue confirming that the land bridge that connected Sesame Island to the mainland was mainly grassland.   Why?  Because the Sesame Monsters were rain forest tree dwellers, and the Big Birds were marshland creatures.   If the land bridge had included jungles and rain forests, then the invaders would have included tree predators like leopards and jaguars as well as smaller cats and weasels, it would have included competitors like monkeys and apes, and the Sesame Monsters would have been driven to extinction.   The fact that they survived suggests that the land bridge was not carrying those species, and not supporting that habitat.   By the same token, the slow moving Big Birds would have been vulnerable to marsh predators and competitors, had they been able to cross on the land bridge, but the habitats of the land bridge did not support those kinds of animals, so they never crossed.

So, as noted, what were probably crossing the land bridge were grasslands species, wiping out the Sesame Island life in their path, and precipitating a mass extinction of much of Sesame's animal life.    But specialized as the interlopers were, they couldn't push into the secure habitats and niches of the survivors.

Now, here is where things get interesting.  Neither the Sesame Monsters, nor the Snuffleupagas nor the Big Birds seem to have much natural fear.   Rather, like the Tortoises, Birds and Lizards of the Galapagos, and like the extinct Moas and Dodos, they seem to have no fear of man or predators.   Their Island, like these others, was probably idyllicly Predator free.
In the case of the Big Birds and Sesame Monsters, that was probably their condition from the beginning.  They grew up in Eden.  But at the same time, there must have been predators that came over with the Snuffleupagas ancestors.

What happened to them?   Population dynamics.   Let's assume that the land bridge was temporary, open only for a relatively short time, long enough for interlopers like Mammoths to come over, but not for much longer than that.

The newly introduced predators encounter an Island full of slow, fat, easy prey.   So of course, they start killing and eating, and breeding.   Their population skyrockets.   Soon there are lots of predators.

Now, in normal ecologies, what you've got is a situation where predators and prey are relatively evenly matched.   What this means is that the prey are able to reproduce fast enough, or to maintain large enough numbers, and the predators have enough trouble catching them, that the populations remain in rough balance.

On the other hand, when the Predators have a huge advantage over the prey, then they kill and eat at will.   The more they kill and eat, the more they can reproduce.  The more of them there are to kill and eat and reproduce.

Until of course, the prey population starts to collapse.   Then it starts to get interesting.  The predator population keeps on growing, but the prey population is dropping.  What this means is that hunting pressure by increasing numbers of predators on fewer and fewer individual prey keeps going up.  No predator willingly starves to let his brother eat, instead, the competition gets fierce and the pressure increases dramatically.   The prey population implodes, with more and more chasing fewer and fewer, until the prey are literally extinct.

Bad news for predators on Sesame Island.   So what do they do?   Well, in the normal course of things, it would all straighten out in the long run.  Sesame Island is being colonized by mainland herbivore species who have been the traditional prey.  In fact, they've been kind of liking it, since most of the hunting pressure is on the easier to catch local species, they've been quietly moving into niches.

The trouble is that when the local species collapse the predators are at the top of their boom cycle.   There are lots and lots of predators, the ratio of predators of any sort to territory is a lot higher than normal.   On the other hand, the population of interloping herbivores and prey species has not fully established itself.  It takes a lot longer to grow a critter than it does to kill and eat.  Over time, their population would expand and stabilize, but right now, they're underpopulated.

So, there's lots and lots of hungry, starving predators who have finished off the local species, and who are now going to work hard on the undersized population of new interloper species.   Under major pressure, that population too collapses.

And the predators all starve, their population collapsing into local extinction.

Actually, this sort of thing happens more frequently than you'd like to think.   A while back, someone charted populations of Lynxes and Rabbits in the wild and found their populations leapfrogged each other.  Essentially, rabbits found the Lynxes few and far between and the landscape green and chewy and started breeding like... well... rabbits.  Lynxes would eat the rabbits, the more rabbits, the more Lynxes.  Eventually though, the population of rabbits would reach the limits of food supply, but the population of Lynxes would keep on swelling.   Then suddenly, one day, there's way too many Lynxes chasing too few rabbits, the rabbit population collapses, and a while later, the Lynx population collapses.   After a few years, the rabbits start the whole thing going again.

The difference, however, is that the Lynxes and Rabbits are inhabiting North America, so there's a lot more room to survive.   The last Lynx never manages to kill the last rabbit. The population collapse is never total.  There's always a few on the margins somewhere who hang on to start the whole thing over again.   But Sesame is an Island, and not a very big one comparatively.   It's ecology is in flux, its not part of a stable pattern.  There are a lot of Lynxes and not that many rabbits, and when the last rabbit is killed, well, there ain't no more where that came from.

The fact is that extinction is not an uncommon phenomenon, and it doesn't usually take an asteroid hitting, or a super-killer species (like us), or even two continents joining.   Most times, extinction comes as a result of painting yourself into a corner, and Island life makes that a much bigger risk.

But anyway, back to Sesame Island's new population of immigrant predators:    There's nothing left on the island to eat.   The only prey are inaccessible, the Sesame Monsters sitting high atop rain forest canopies, the Big Birds standing in the swamps with their eggs tucked under their arms or the Mammoths who are just too damned big and ornery to take down.

So the predators starve.  Or they eat each other, which cuts down the population but only postpones starvation.   And eventually, no more predators.

Trapped on the Island, unhindered by possible Predators, and with all the smaller mammal rivals hunted to extinction, the Southern Mammoths start reducing, ending up as the pygmy Snuffleupagas, who proves to be a quiet and genial neighbor, uninterested in competing with or bothering the Big Birds or the Sesame Monsters.

Sesame Island goes back to its sleepy ways, but now there are very few species.  The species that are left, are quite advanced and sophisticated, well adapted for their niches.

But there are all sorts of newly vacated niches.  There's neither predators nor competition to keep the Sesame monsters from moving into these niches.   And in occupying these niches, there is an adaptive pressure to change, to make the fit a little better.

So once again, they speciate.  But the new species or new occupiers on the niches will be variations on the survivors.   So, for instance, we might see ground dwelling bush Sesame Monsters developing robust teeth for chomping on tougher vegetation, or different patterns of fur, or even furless Sesame Monsters, new features might include horns, larger or smaller eyes, specialized adaptations.

Now,  we have to make some important observations on this speciation.   The variant Sesame Monsters have hundreds of years or even millions to adapt to their new niches, so we can expect to see some changes.   Nevertheless, even a few million years of adaptation will not give us the diversity of forms and species we would see in a non-impacted landscape.

I mean, look at a modern landscape, and what do you see?   Rabbits, antelopes, rats, deer, foxes, cats, mice, wolves, etc. etc.   There are a series of creatures occupying different niches with radically different forms, behaviours, strategies and lifestyles.   Part of this is driven by the fact that they're occupying different ecological niches.   But a large part of it is also that they have long and differing lineages.   There's twenty million years between dogs and cats, forty million years between a rabbit and an antelope, there's eighty million years between a rat and a deer.   All the animals in the landscape are coming from different ancestor species, who in turn came from different ancestors and so on, and they've had tens upon tens of millions of years to develop apart.

Now, in contrast, take a look at dogs.   Specifically, take a look at all the bewildering forms of dogs, from St. Bernards and Great Danes, Sheepdogs and Collies, to Huskies, Retrievers, Poodles and Chihuahas, we see a diversity that almost mimics a natural landscape in some ways.

The key is ‘almost’ and ‘in some ways.’   Each breed of dog no matter how colossal, or deviant, no matter whether the ponderous St. Bernard, the streamlined greyhound or elongated dachshund remains clearly a dog.   The skeletal and skull and foot morphology is the same, the dental structure and dietary parameters are the same, the brain structure, the ingrained behaviour and social processes are consistent.   No matter how far a particular breed of dog pushes the range, the creature is still a dog, and clearly one with its peers.

The finches of the Galapagos underwent an adaptive radiation that was remarkable in its own right.  But the finches clearly remained finches.

So, the point is that the Sesame Monsters, even when adapting to new niches, will still remain Sesame Monsters.  They might get bigger or smaller, sport horns, develop larger teeth.  But in most physical ways, including in most cases, size, general proportions, skeletal features, internal anatomy, neural wiring and behavioural traits.... the apple is not going to fall far from the tree.

For instance, most will probably fall into the same size ranges as normal Sesame Monsters, most will be left handed, most will be four fingered.   Where an animal departs from the norm in some specific way, it may conform to the norms in most other respects.   The differences and departures will be cosmetic.   After all, the divergence is from a highly adapted, relatively specialized and sophisticated animal, and although they're moving into new niches, there's no geographical isolation, so its unlikely that we're going to get true speciation.    All the variants will be closely related, and perhaps capable of interbreeding.   So at best, we may be looking at subspecies, or perhaps merely variant breeds within a species.

This allows us to speculate a bit.  For instance, the drummer, Animal, may be a push browser, developing heavy teeth for chomping.   Is Rolf really a dog or simply a ground dwelling, long eared Sesame Monster who is occupying a gorilla's niche and bulking up.   Is Kermit really a frog, or simply a marsh adapted Sesame Monster whose particular adaptations are furlessness, green skin and a wedge shaped mouth.

We can expect that the same processes would take place for the descendants of Big Bird, the main line of Big Birds will continue to dominate.  But the opening of new niches will allow for adaptation and speciation.   We might see new or specialized offshoots of the Big Birds, including small dark forms with crooked beaks occupying some peculiar niche and with an affinity for chickens, or perhaps a big mid-sized, solitary, hook-nosed, bald bird.

In short, what we would be seeing, potentially, is a proliferation of the non-standard Sesame Monsters, the variant creature types.  In some cases, analysis of their physical differences might allow us to guess at their niches and lifestyles.  In other cases, it's a wild stab in the dark.  But the point is that we can place them biologically within the evolutionary history of Sesame Island.

Now one last thought, before we depart.   How do we get from Sesame Island somewhere off the Asian shores of the Indian Ocean to Sesame Street in New York?

Well, I think its probably a mistake to assume that Sesame Island goes undiscovered.  Instead, if we looked around to folklore or fiction, I suspect that we'd find reports or stories of a mysterious Island of talking animals.

The region around the Indian ocean's Asian shorelines, the most likely location for Sesame Island was relatively well traveled for at least the last fifteen hundred years.   Malays and Indonesians settled the Indonesian archipelago.   Malayan seafarers colonized Madagascar approximately 1500 to 2000 years ago.   Sometime after that, Muslim sailed along the shorelines of India to make converts as far east as the Philippine Moro Islands.   In turn, Indian merchants and traders dotted the east coast of Africa, establishing cities like Zanzibar.  The Chinese, during the middle ages, established a huge fleet which sailed along the coasts reaching as far as Africa.

So its likely that Sesame Island could be locally known.   On the other hand, the sailors of India, China, Africa and Malaya tended not to go far from land.  Most of their sailing expeditions were short jaunts along well established routes, hugging the shorelines.   Thus, large islands in the deep Indian Ocean, such as Mauritius, Reunion, the various Islands of giant tortoises, the Crozet and Kerguelen archipelagos remained undiscovered until European sailors.

Sesame Island was perhaps a few dozen to a couple of hundred miles from the mainland.   It's likely that it would have been known of, or discovered or rediscovered from time to time.  On the other hand, depending on wind and current, it might well have escaped discovery for much of its history.

Even if it was discovered, we could conceive that it was far enough away that it was not reachable by aboriginal tribes, but only by the more civilized sailing societies.   And these societies would have encountered a strange land of talking, humanlike animals.  They may well have chosen to give it a wide berth.  Many of the strange fauna of Madagascar were left strictly alone by the Malay settlers, described as tabu or supernatural.

It's worth noting as well that even in the event of human settlement, much of the Island habitats would not be troubled by human agriculture and subsistence forestry.   Indeed, humans were particular in the territories that they settled, agricultural or fishing villages generally didn't tend to locate in deep marshes, or tropical rainforests.   There might have been some habitat infringement, and perhaps new species and diseases introduced.  But the Sesame Island creatures would have had centuries, perhaps even millennia to adapt, and the most vulnerable life forms were already long extinct.
From there, we can assume that Sesame Island was discovered by Portuguese traders in the 16th century, by the Dutch in the 17th, and eventually taken as a colonial territory by either the French, British or Dutch in the 18th or 19th century.   They were probably described, and specimens living or dead transported back to Europe in the 16th or 17th century, but they would have been more curiosities.   The colonial nations of the period from the 16th through the 19th centuries were more interested in profit and commerce than science or novelty.  The members of the various Island races might have started showing up in European royal courts, zoos and circuses as early as the 18th and 19th centuries.

It would not have been until the late era of the 19th century, say from circa 1860 onwards, and the growth of educated and literate European and American middle classes that the Sesame creatures, probably named Muy-Pahts from the Thai language, or Mu-Pets based on post-Darwinian notions of a lost continent of Lemuria or Mu, would have become popular.

From that point, there would have been a serious public demand for the creatures in zoos or circuses, or for private collectors.   Darwin had become popular, and the creatures would have been in great demand as object lessons and missing links.      During this period, particularly 1870 to 1950, anthromorphized animals were popular, thus monkeys were made to wear little suits, trained bears wore hats, apes were put in dresses.   The popular motif was to have animals dressing and acting in parodies of human behaviour.   In this light, the Mu-Pets, particularly the Sesame Monsters were popular in the roles.   This was probably a period where many Mu-Pets were absorbed into human culture, dressed in human clothes, taught human roles and trained to enact scenes of human pageantry, from the Wild West to the age of Buccanneers.

There's a question of course, as to how well they would do in captivity.  They were fundamentally wild animals occupying specialized habitat with particular diets.  Moving them into the stressful situations of circuses and zoos would have put pressure on them, exposed them to parasites, diseases, malnutrition and obesity from bad diets and chronic social stress.   So many of the captured animals, particularly of the first generation, would not have done well.

The evidence from Sesame Street the television show is that these are long lived creatures, possibly their lives are equivalent to human spans.  They would tend to reproduce slowly, and their young would probably be vulnerable.   So its likely that hunting pressure to fill the burgeoning needs of zoos and circuses would probably have impacted the Island population.

So how does this explain the Sesame Street colony of Mu-Pets?   The most likely explanation is that they were from a circus that went bankrupt or otherwise failed somewhere in the 1920's or 1930's.  Most of the circus performers would have gone on to other circuses or found normal jobs.  The dangerous or unwieldy animals would have either been purchased by other circuses, found their way to zoos or been put down.   Indeed, if times were hard on circuses, it would have probably been cheapest to simply kill off the wild animals.

The exceptions would have been horses, who could have been re-deployed for other work, and the Sesame street creatures, who by and large, were non-aggressive, posed no threats to the community at large, and were small enough (even the Big Birds) that they could thrive scavenging in urban environments.   Also, its damned hard to shoot something that can talk to you, and whose manner is so childlike.  The most likely explanation is that the Sesame Street colony are the descendants of a failed circus.

Another possibility is that these animals were pets who either escaped or were abandoned.   Indeed, there's now a well established history of exotic pets who become all the rage, such as baby alligators, vietnamese pot bellied pigs, parrots.   However, over time, the novelty or thrill wears off, peoples circumstances or interests changes, the pets grow too big or aggressive, or for one reason or another, the pets are disposed of, one way or another.

Baby alligators were flushed down the toilet.  Vietnamese Pot-Bellied pigs were put down.  Parrots are an interesting case because they often outlive the lifestyles or commitments of their owners.

One of my neighbors has a parrot colony in their living room, they have more than a dozen birds of almost as many species, ranging from cockatoos to macaws to norwegian blues.   They didn't set out to collect parrots, but what happened was that from time to time, people who had parrots found that they didn't want to keep them.   Either they were changing jobs or homes, going through divorces, having medical or financial problems, or simply bored with the birds.   The thing is, these critters don't die.  Their lifespans are comparable to humans, which means that Parrots will probably outlive most marriages, will outlive careers, will outlive batchelorhood, and most of your child's adolescence.   Owning a parrot is a lifetime commitment, in an age where a lot of people have trouble signing a lease for a year.   Anyway, the bottom line is that people wanted to get rid of their parrots, and so they'd just sort of dump them on my neighbor, which is how he got such an extraordinary collection of birds.

So here's an alternate explanation for the Sesame Street colony.   Perhaps they're simply abandoned pets who wound up congregating for their need for society.  Indeed, people bent on abandoning their Sesame Monsters might well drop them off at a colony or near other wild monsters so that they can learn to fend for themselves.   Or they might have been dropped off at some informal sanctuary, like my Parrot keeping neighbors, and then simply made a gradual transition to independence, or outlived their sanctuary keeper.

Or possibly, they're simply escapees who sought each other out and founded or joined wild colonies.
One thing is for sure, the population of Sesame Street is definitely a wild colony and not a circus or zoo troop, they're co-existing with humans, but don't seem to be owned.

The phenomenon of transplanted populations is not common, but its not unheard of.   In England, there's a small herd of wild wallabies who are living comfortably in a corner of the English countryside.   In New Brunswick, my home province, there was a famous incident where a couple of Japanese Macaques escaped into the wild, they were well adapted to New Brunswick climates, and there was some concern that they might found a breeding colony.   There's a long record of Europeans introducing foreign species, usually domesticated or semi-domesticated, which then take off.   Horses in North America are an excellent example.   Rabbits in Australia are another.

Indeed, we see colonies of wild but human encultured Mu-Pets in several cities and countries.   For instance, colonies have been identified in urban districts in France, Canada, Brazil, Japan and Australia.   Some experts suggest that in addition to zoos and circuses, there may be as many as thirty wild colonies, mostly in cities throughout the world.

The Sesame creatures, because of their ability to learn and speak human languages, their non-aggressive ways, and their intelligence would be well suited to scavenging at the fringes of human cultures.   In a way, they'd be a lot like other urban invaders, including rats, skunks, pigeons and particularly raccoons.  So there's every reason to think that they would be quite successful.

Indeed, they might be more than successful.  For their part, the Sesame creatures are friendly and non-aggressive, they pose no threats, make few if any demands, and do not amount to a nuisance.   So in this sense, they're actually more adept than even rats, pigeons and raccoons at surviving among humans.

The evidence is that the individuals of the Sesame Street colony not only survive among humans, but they're tolerated and actively embraced.   There are numerous documented instances of humans on Sesame Street forming friendships with the wild animals, assisting them and protecting them.   It appears that there is a long standing tradition, a well established part of the local culture of Sesame Street, to look out for and protect the members of the Mu-Pets colony.

On the other hand, its probably not long term success.   The Sesame Street colony, and other identified colonies in other cities are usually quite small.   Take both Big Bird and Snuffleupagas.   They appear to be sole representatives or at most the products of small family groups.  Big Bird might have an aunt and a younger sister, his parents are absent.   Snuffleupagas has parents and a sibling.  But in both cases the populations are single family groups.  Clearly, both of these animals are going to have a hard time finding mates.  There's a good chance that neither may reproduce, or if they do mate, it will be within their immediate family grouping.   There are simply not enough of these animals, absent an external breeding program, to sustain their population.  In a generation or two, both the Snuffleupagas and Big Birds of New York might well be extinct.

The situation of Sesame Monsters is a little bit better.   Their small size, adaptability, and human-like features made them far more desirable for pets, zoos and circuses, so larger numbers of them found their way into the human world.  Moreover, their assets also allowed them to survive most effectively when reverting to the wild in urban areas.   So its not a surprise that the majority of Sesame creatures in urban colonies are Sesame Monsters.

But having said that, their situation is not that great.  Their populations are small and isolated.  While there are enough individuals on Sesame Street to form a borderline viable breeding population, inbreeding is a constant danger, and accidents or disease can cripple a populations reproductive capacity.   It's likely that in the long run, the Sesame Street colony, and most urban colonies will fade away.

One solution is to arrange for outbreeding programs, transferring Sesame creatures from other urban colonies, or from Sesame Island to mate with local colonies.   This may be the only hope for the Big Birds of Snuffleupagas in many places.   And it may be critical to maintaining the viability and genetic diversity of the Sesame Monsters.

But of course, there are obstacles of various sorts, including jurisdictional problems.  One issue for the Sesame Monsters and their allies is that they have so thoroughly embedded in local human culture and language, that this may actually form a barrier to mating.   An English speaking Sesame Monster may simply refuse to bond and mate with a French speaking Sesame monster because their mating communication will not synch up.

In any event, by all indications, the Sesame Street colony has been around for a long time.   The Sesame Street children's show has been around since the 1969s and the colony was well established even then.   Some of the residents of Sesame Street, such as Mr. Hooper, were quite old even then but were familiar with and comfortable with the creatures.   This long and comfortable relationship suggests that the Colony dates back several decades.

Let's hope that the marvellous creatures of the Sesame Street colony will endure for many, many more decades.