I’ve often said that turtles (in the broadest, Americanesque, sense of the term) haven’t been sufficiently covered at TetZoo. Even today this remains true, despite efforts…
Caption: Eastie vs rat head. Image: Mathew Wedel, used with permission.
Some considerable time ago I showcased photos of Eastie the box turtle, a pet owned by friend and colleague Mathew Wedel. Eastie is a Box turtle Terrapene carolina, and thus not a tortoise in the strict sense (Terrapene is an emydid, not a testudinid). But whatever. As discussed in this 2014 TetZoo ver 3 article, Eastie one day found part of a deceased rat’s head while on a backyard jaunt, and proceeded to deliberately snip away at the broken braincase and eat the bone fragments. This bone-eating carried on for about 20 minutes, and Matt thought it interesting enough to take the photo you see here (part of a sequence).
Most people familiar with tortoises (and other turtles) know of cases where the animals consume bones, chew on bones, or even chomp on carcases. This happens enough that we might class tortoises as opportunistic scavengers or omnivores more than herbivores. Relevant here (I previously mentioned it in that 2014 article) is the photo in David Attenborough’s Life on Earth (taken by Attenborough himself) that shows an Aldabran giant tortoise Aldabrachelys gigantea scavenging on the carcass of a conspecific (Attenborough 1984). It’s not entirely clear what the tortoise is doing, but it looks like it’s gnawing at dried skin and muscle, not bone.
Caption: Aldabran giant tortoise and Aldabran giant tortoise, one in healthier state than other. Image: (c) David Attenborough.
Rather more grisly is the photo below (here’s your warning to not scroll down if you want to avoid seeing it), obviously from a captive setting, where a group of Indotestudo* tortoises are scavenging on what appears to be a deceased rat. They’re clearly going at it with some fair degree of gusto - look at those guys, literally tearing away at what appears to be skin and internal organs. I forget where I found this photo, and a quick search online hasn’t revealed its source. It mostly appears on meme sites, accompanied by some amusing caption (“When Master Splinter doesn’t bring pizza” or such)…
* Thanks to Jeannot Tihoti Maha'a for the correction.
Caption: your ‘mammals vs reptiles’ image of the day.
As is well known, turtles are ‘calcium hungry’ beasts. As we’ve seen already, they eat bone and bone fragments when they discover it, and they’ll even eat bone fragments out of dried scat produced by cats and other predators (Bally 1946, Loveridge & Williams 1957). They’ll also return to a given piece of bone just seconds after the observing humans have moved away (Esque & Peters 1994), something they don’t ordinarily do on being disturbed. And they’ll also swallow stones, mouthfuls of sediment and even mine for specific sediments in some places (again, this was the topic of the 2014 TetZoo article I’ve already mentioned).
All of that makes sense, and can be linked to their requirement for shell growth and, in cases, egg production and so on. The consumption of animal matter as per the Attenborough and Master Splinter photos, however, isn’t necessarily explained by the same thing. They might instead simply be reflective of the fact that the vast majority of animals that mostly subsist on plant material are also very keen to consume flesh and other tissues as and when the opportunity arises - a subject I’ve covered at TetZoo a few times before, follow the links for more…
Tet Zoo picture of the day # 11 (Styracosaurus eats carrion), June 2007
Duiker, rhymes with biker, August 2008
Hippos are photographed biting a crocodile to death, November 2009
Lal the chicken-eating cow, December 2010
Turtles that eat bone, rocks and soil, and turtles that mine, April 2014
Refs - -
Attenborough, D. 1984. The Living Planet. Collins, London.
Bally, P. 1946. Tortoises eating bones. East African Uganda Natural History Society 18, 163.
Loveridge, A. & Williams, E. 1957. Revision of the African tortoises and turtles of the suborder Cryptodira. Bulletin of the Museum of Comparative Zoology 115, 163-557.
