Elephants walk on their tippy-toes
Researchers analyzed the foot pressure distribution in African and Asian elephants to determine why foot diseases arise in elephants in captivity when the same foot diseases are rare in the wild. Their results, published in the journal Royal Society of Open Science, showed both Asian and African elephants put most pressure on the "lateral digits of their feet", or toes farthest away from the body.
Elephants are so large and heavy that without specialized adaptations they would be crushed under their own weight. In fact, they are the largest living land animal, with some reaching over 17,600 lbs, or 8,000 kg. With all this weight, it's no surprise elephants in captivity will often develop foot diseases. What's not yet clear, however, is whether being in captivity causes the diseases or if there's something in the enclosures causing them.
To answer this, researchers looked at weight distribution patterns on both African and Asian elephants. They found that, when walking, elephants first applied most of the pressure to specialized false toes of the foot, called predigits, and then shift the weight gradually towards the body.
These predigits help carry the enormous load from the feet all the way up the leg, and are implanted in a massive pad of fat that make up the elephants feet. The elephants applied most of the pressure to the 3rd, 4th and 5th digits, and used "mainly the front part of their feet to produce vertical forces as they roll over the fat pad during ground contact", according to the study.
Not coincidentally, these outer digits are where foot diseases are typically found.
Elephants in Captivity
Elephant adaptations such as the fat pad and false toes work great when the animals are in the wild. But what happens when they're no longer standing on softer dirt?
Unfortunately, in captivity some elephants develop diseases such as abnormal walking, infections, joint stiffness, and limb lameness. These diseases are uncommon in the wild, and can be quite dangerous to treat for both the elephant and care givers due to the elephants size.
According to the study, enclosures that have more natural materials should result in less foot diseases (and happier times for everyone involved).
Olga Panagiotopoulou, Todd C. Pataky, Madeleine Day, Michael C. Hensman, Sean Hensman, John R. Hutchinson, Christofer J. Clemente. Published 5 October 2016. DOI: 10.1098/rsos.160203