I have seen biologists on tv record weights of captured animals as part of their research, but unlike sloths or mastodons, they can just use a scale. But talking about weight has brought up in my mind a couple other examples of the perils of estimating weight.

One is the short faced bear, Arctodus simus. Quite some time ago i got into a debate with someone over the feeding habits of the big bear, which also involved weight. He didn’t think the bear was as big as often cited. One of my sources listed a weight of 830 pounds, but that was based on body, and should be taken with caution. Femoral cross-section yielded 850 for females, and one big male from Utah was estimated to be over 1300 pounds. He said limb bones are not useful, because Arctodus was proportioned differently, and hence only looks huge because of its long legs, and was no bigger than a Kodiak. But Kodiaks (at least according to the figures i have heard) can reach 1500 pounds. He also tried using a reconstruction as evidence. I tried to tell him that reconstructing an extinct animal known only from bones is problematic, and hence a reconstruction should not be used to back a claim. Besides, paleo artists get their info from scientists, who seem at odds on the bear’s weight. your blog showed me just how much weight can reveal about an animal. And now it looks like it would have even more to tell us about Arctodus.

“Max” also comes to mind. He’s a mastodon found in Diamond Valley, CA. A skull, tusks, some vertebra, a few ribs, a pelvis, and the distal end of the femur. But he bears the title of the largest mastodon from the western US. They were able to gauge his size based on that distal femur. The whole process wasn’t explained, so that estimate is likely as far up in the air as your sloth. But yeah, there are lots of Megalonyx remains out there. Use the method on them and see how they measure to your sloth.