Grizzly sow in Yellowstone spotted with 5 cubs

The mama bears are out and about in Yellowstone again, and this year, there’s an extremely rare occurrence – a grizzly mother with five cubs.

A story on WyoFile caught my eye last week. Mike Koshmrl reported that there’s a grizzly bear in Yellowstone who has five cubs with her. He noted that one to three cubs are normal, but that occasionally, a sow will have four. The storied Grizzly 399 emerged from her den in the spring of 2020 with four cubs in tow, and that was only the 11th time since the state began monitoring grizzlies 50 years ago that a sow has had quadruplets.

Five cubs would be a first.

Koshmrl interviewed Frank van Manen, who runs the Interagency Grizzly Bear Study Team. Van Manen explained that sometimes, a sow with cubs will take on the cubs of a sister, though even that is rare. That may well be the case with this pack of five cubs. Van Manen noted that if they somehow are able to get genetic samples from each of the cubs, they could know for sure whether the young bears are siblings or not. If that happens, it would be the first recorded five-cub litter in the Yellowstone area.

A Jackson man, Tim Mayo, got a picture last fall of a five-cub litter of black bears. He caught the brood on camera, and he submitted the image to WyoFile.

Unfortunately, it’s not likely all five of the cubs of either the grizzly sow or the black bear sow will survive to adulthood. Even single or twin cubs have a difficult future. And with more grizzlies in the Yellowstone area than there have been in decades, the biggest threats to these cubs are the males of their own species – and possibly even their own fathers. Bruins will kill cubs they run across.

No one knows if they’ll make it, just like nobody knows if they’re truly quintuplets. But one thing is certain – they’ll bring plenty of visitors to Yellowstone this year hoping to catch a glimpse of a rare five-cub litter.