Inside the dig with intern Leo

Leo Hey everyone, my name is Leo. I'm an intern here at Waco Mammoth National Monument, and I'm answering some questions that Gabriel here is going to ask me.

Leo Yeah, you're exactly right. All of these animals did live during a time scientists would call the Pleistocene Epoch, which you might know better as the Ice Age. This stretch of time took place between 2.6 million years ago and 11,700 years ago. But we do have different layers here in time that are thousands of years apart from within that Ice Age. What we're looking at is an assemblage where we found the first and so far only known nursery herd of Columbian mammoths.

Leo Oh yeah, great observations. So right now we're looking at Mammoth Q, and he is the only adult male at our site. He is, in fact, missing a few pieces, and we think the main reason is that he was scavenged on after he died. On the back of his kneecap bone — his patella — there are a few bite marks from a dog-like animal. There are also rodent marks on his shoulder blade, his scapula, from mice or rats that were chewing on it after he died. This is all evidence of scavenging, and that's why we think a lot of his back legs are actually missing.

Leo Excellent questions. So yes, we do have a western camel — scientific name Camelops hesternus — and this was actually the last species of camel known to be living in North America before all the camels here went extinct. We've got a camel here even though we don't have camels in North America today, because camels are actually originally from North America. The earliest species, Poebrotherium, lived about 43 to 45 million years ago in what is now South Dakota. These were very small animals, about two feet long — about the size of a goat. But millions of years later in the Pleistocene, we've got larger species like the western camel, which could be seven feet tall at the shoulder and about 11 feet tall at the head.

Leo We did in fact have giant tortoises here at the time of the Ice Age, and this gives us more information about what the environment was like. It was more temperate than it is today — more humid and warmer. So even though it was the Ice Age, Waco would have been only about 10 degrees cooler on average than it is today — think more like Kansas or Nebraska. And yes, that bit of rock you mentioned is actually a layer slightly above the western camel, and we think it contains the foot bone of an animal, but we're not sure what animal yet.

Leo Oh, we're pretty sure there's more to be found because we're making new discoveries every year. In fact, when they were building this building, they were digging holes for the support pillars and they accidentally hit bone. Recently, there was water leaking from our HVAC unit — a machine that keeps the temperature and humidity levels constant — and when we were removing dirt from the rock wall, we actually uncovered even more bones. This place seems to be chock full of bones as far as we can tell. Just imagine how many new animals we'll find in the next few years as we keep digging.

Leo That's a great question, and we do have a lot of questions about the animals we've found here. It's looking right now like the saber-toothed cat and that even-toed mammal might have been on the same layer as that foot bone I mentioned — possibly a fourth layer here at our site, somewhere between the layer where Mammoth Q is and the layer where Mammoth W is. We're just not sure yet. But yes, we do in fact have a saber-toothed cat tooth here. It is a baby tooth, and on display we only have the replica because baby saber-toothed cat teeth are very rare and fragile. This tells us that saber-toothed cats were living here in the area during the Ice Age.

Leo These pillars right here — like this one next to Mammoth Q and a bit farther to the back of the building — are what we call witness columns. They were left here when we were excavating to remind us where the surface of the ground was before we started digging. So we can get an idea of just how deep it is compared to where we found these animals.

Leo Hey, that's all right. And I forgot to mention this at the beginning, but I am an intern through the Student Conservation Association — a federal intern working with the National Park Service.

Leo Thank you for the interview.