Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff, Lauren Vogelbaum Here, there are currently eight different species of bears living here with us on planet Earth, but it's a bit more complicated than that. We'll take, for instance, the brown bear, whose range extends from the United States through Canada and far into China, Russia, and Scandinavia. There are many subspecies of brown bear that hang out in very specific nooks and crannies the Gobi Desert, for instance,
or the Russian peninsula of Camchaca. But the largest of the brown bear subspecies is the Kodiak bear, which lives only on the Kodiak Archipelago off the southern coast of Alaska. The brown bear species is believed to have first evolved in Asia and spread into Europe around two hundred and fifty thousand years ago. Around a hundred thousand years ago, they likely moved into North America through Alaska, but didn't go farther south into the Lower forty eight until closer
to between thirteen thousand and fifteen thousand years ago. For the article, this episode is based on How Stuff Work. Spoke by email with Shannon Finnegan, a PhD. Candidate at the State University of New York and a Kodiak bear researcher at the Alaska Department of Fishing Game Kodiak And. She said it's hard to say exactly how brown bears ended up in Kodiak, but the most agreed upon theory is that they likely crossed over from mainland Alaska via
an ice bridge during the last ice age. It's believed that some of southern Kodiak may have been unglaciated at this point, and the first Kodiak brown bear population may have taken hold here. As the glacier retreated, the bear population likely expanded to occur all across the archipelago, taking advantage of the rich food supplies. The Kodiak Archipelago is a string of islands cut off from mainland Alaska, which
is the perfect condition for a subspecies of anything to evolve. However, while distinguishing between similar animal species can be difficult, defining subspecies is even trickier. Biologists don't even completely agree about whether different groups of brown bears should be classified as subspecies or not. Finnigand said, generally speaking, all brown bears found across the world belonged to the same species. However, it is said that brown bears could be split into
five clades based on some genetic and geographical differences. Within this clade system, Kodiak bears fit into a clade with bears from mainland Alaska. Clades are branches of evolution that include a single common ancestor and all of its descendants. Since the Kodiak bear has been living the island life for at least twelve thousand years, it's been cut off from others of its species for long enough to display
some genetic differences. For instance, the Kodiak bear can grow to larger sizes than any other type of brown bear, weighing in it up to one thousand, five hundred pounds that's six d and eighty kilos. They rival the polar bear for the title of biggest bear in the world. And there's another reason Kodiak bears grow so large compared with their mainland counterparts. Their archipelago is rich in food like Pacific salmon, and there's relatively little competition from other predators.
Bears may have a reputation for being aggressive, but according to Finnegan, Kodiak bears have harmoniously cohabitated with humans on their islands for a long time. There hasn't been a human fatality from a bear attack on Kodiak in over ninety years. Finnegan said they are extremely adaptable and curious animals with very distinctive personalities. Some bears around the city of Kodiak have even learned how to open car doors and bear proof dumpsters, which are very tricky to try
and access human foods. Kodiak bears, like all brown bears, have the ability to delay implantation of a fertilized egg in the womb. That's how a female brown bear can give birth to a litter of cubs, all sired by different fathers. They usually breed in June, but won't become pregnant until later in the fall. Their bodies have to wait to see whether they can build up enough fat reserves to sustain a pregnancy and provide milk for offspring
in the den. Kodiak bear populations seemed to be relatively stable at around three thousand, five hundred individuals on the archipelago. However, this wasn't always the case, Finnigan said. Historically, Kodiak bears were heavily persecuted on parts of the archipelago when cattle ranching was a prominent industry, they were viewed as vermin and exterminated whenever possible. Hunting groups on Kodiak took issue against this and fought to have protections put in place
for the Kodiak bear. Thanks to the efforts of these sport hunters, huge swaths of land were set aside as protected refuge for this bear and their popular and increased illegal hunting of Kodiak bears does exist today, however, the population is closely managed, but as with many animal populations, climate change may impact Kodiak bears in the future, particularly if warming waters alter or negatively impact the Pacific salmon
that they rely on for food. Today's episode is based on the article Alaska's Kodiak Bear is one of the Planet's biggest on how stuff works dot Com, written by Jescelin Shields. Brain Stuff is production of I Heart Radio in partnership with how stuff Works dot Com, and it's produced by Tyler Plain. Of four more podcasts from my heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.