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Sloth bear cub update: It’s twins!

Posted by: Rebecca Whitham, Communications

Surprise! We’re excited to announce that we have not one, but two sloth bear cubs doing well behind the scenes at Woodland Park Zoo. It turns out our big news about having a cub born back in December is even bigger news, now that we know we have twins!

Video: Sloth bear mom Tasha leaves the maternity den briefly, lured by a snack of crickets offered by zookeepers, revealing the two cubs she birthed on December 18.

The case of the hidden sloth bear cub
Back on December 18 when the cubs were born, 7-year-old mother Tasha was so quick to build a fortress of hay around her cubs to protect and support them in the maternity den, that we never got much of a visual on the litter. We spotted one cub, but we suspected there was a second cub in the litter, hiding out from where we could see it.

What made us think we had two cubs? Through baby monitors, keepers could hear what sounded like two cubs breathing, grunting and nursing. But since we couldn't see the second cub, we didn't want to count our chickens before they hatched (or, errr, count our cubs before visual confirmation). We happily came out with the news about our one confirmed cub, but we kept our eyes and ears focused on finding any clues that the second cub wasn't just a figment of our imaginations.

Hearing double
As the weeks went by, Tasha’s formidable hay fortress continued to prevent our efforts to spot the cubs. The occasional glimpse we got through the web cam keepers had set up in the maternity den was never enough to confirm two cubs in one place at one time. But from the audio we were picking up, it was clear we were hearing two strong, nursing vocalizations. Keepers were so confident they had a second cub back there that even though they still didn't have visual confirmation, we went ahead and officially gave the cub an identification number and added it to our record books.

Video: Keepers listen to the cubs via a baby monitor while watching the maternity den cam. They use a decibel reader to help pick out the two voices.

And then it happened.

Getting the first look at the second cub
An eagle-eyed keeper was watching the cam when she spotted the break in the case of the hidden cub that we’d been waiting for.

Can you spot the two cubs with mom? Image captured from an internal web cam.

Hard to tell what you’re looking at, huh? Now you can see why this was such a challenge! Here is video from that scene where you can see a little more clearly the two cubs cuddled up on Tasha.

The proof is in! So it is now with great pleasure that we officially welcome sloth bear cub number 2 to the Woodland Park Zoo family. With the loss of the cubs’ father, Randy, to cancer just a week ago, we treasure this second gift even more now, knowing Randy’s legacy gets to live on doubly. Sloth bears are endangered in the wild and rare in zoos, and these two new conservation ambassadors will bring delight to our visitors and inspire them to learn, care and act on behalf of wildlife.

How can a sloth bear cub be so invisible for so long?
Our sloth bears are off-view now because of construction in their exhibit area, but for those who have spotted them over the years, you might be wondering how these big, hairy beasts could be so invisible to us as babies.

An adult sloth bear who is very much not invisible. Photo by Dennis Dow/Woodland Park Zoo.

Well, sloth bears are born extremely tiny and blind at birth. Although newborn cubs have strong toes and forelegs, they don’t really start to walk until around four weeks, which explains why for the first month, the cubs never ambled into our view, staying hidden by their attentive mother’s side.

The cubs are one month old as of today (happy birthday!), so they’ll by now have opened their eyes, and they are beginning to be more active. They are even growing in some hair! It’ll be another month or two before they start to sample solid foods, though they’ll still be nursing from mom even then.

With these little milestones of independence, we believe we’ll begin to have better opportunities to spot the cubs more regularly. Tasha is a very attentive mother and is hesitant to leave the den. But as we get her more comfortable with taking short breaks away from the den, we’ll eventually be able to get access to the cubs for a quick veterinary check-up in the near future. Whatever little glimpses we’re able to sneak, we’ll be sure to share with you!

Help us build a new home for these endangered bears
Don’t forget that plans for an amazing new home for sloth bears are already underway. This spring we’re opening phase one of the most ambitious new exhibit complex at the zoo since 1996—a complex that will transform the heart of the zoo with new homes for sloth bears, Malayan tigers, Asian small-clawed otters and tropical birds.

Artist drawing of exhibit plans by Mir/Woodland Park Zoo.

The first phase opening this summer will debut with the otters, birds and a nature-play space for kids. With your continued support, we’ll be able to complete the exhibits for the sloth bears and tigers next. Learn more about the plans and how to get involved at


Unknown said…
Congratulations on TWO cubs!
Anonymous said…
Thank you for sharing. What a remarkable opportunity you give all of us to experience the wonders of nature. Do you have any idea what percentage of the time sloth bears have more than one cub? Thanks!
Anonymous said…
It is so wonderful to see the Zoo having so many new babies! I have been going to the Zoo for over 60 years and even used to wander through it as a kid all the time before it became a pay Zoo. I am glad to be a paying contributor now though, to keep it going.
Anonymous said…
Hope you name one of the cubs Randy Jr.
Sue Holmstrom said…
They are so cute - but I love all animals. Can't wait to get to the zoo soon.
Anonymous said…
Cute just keeps getting cuter! Thanks for keeping us in the loop. WPZ rocks!