DINOSAURS & TERMITES

[darren.naish@port.ac.uk]

Dan Varner noted the absence of termite mounds in dinosaur 
restorations. HOWEVER, there is a John Sibbick painting where two 
_Massospondylus_ individuals are surrounded by a load of termite 
mounds (one of the massospondylines is even extending its tongue, 
apparently to lick up termite prey). There is also a Wayne 
Barlowe painting of a therizinosaur digging at and feeding from a 
termite mound AND a William Stout illustration of a _Shanshanosaurus_ 
investigating (but apparently not feeding from) a tall termite mound. 
Stout was presumably inspired by Dong's (?) suggestion that 
_Shanshanosaurus_ was insectivorous. This illustration is in Glut's 
_Dinosaur Encyclopedia_.

Whether or not termites that constructed tall mounds were present in 
the Mesozoic, it seems very doubtful to me that dinosaurs like 
therizinosaurs, ornithomimids or _Deinocheirus_ were true termite 
eaters. This is because (1) they are just too big to have subsisted 
on such tiny prey and (2) they lack, so far as we know, the 
appropriate tools required to collect such prey.

A number of extant groups, including pangolins, aardvarks, echidnas, 
numbats, myrmecophagids (true anteaters), aardwolves and the sloth 
bear, feed predominantly on ants and termites. None of these animals 
is any bigger than, I don't know, about 50 kg or so, so it seems 
likely that this is the maximum size at which formicovo... ant eating 
is possible. The dinosaurs we are thinking of here are much larger - 
in the case of big therizinosaurs and _Deinocheirus_ much, much 
larger. Unrealistic notions of ankylosaurs as possible insectivores 
also fail on this possible criterion.

All modern ant eaters also have specialised mouthparts that allow 
them to collect ants and/or termites with maximum efficiency. 
Pangolins have absurdly long tongues that anchor to their 
xiphisternum - located somewhere around the middle of their belly! 
True anteaters of course, and aardvarks and echidnas also, have very 
long tongues and possess elongate, tubular, almost or entirely 
edentulous, skulls. Aardwolves (_Proteles_) do not have particularly 
long tongues but have enlarged salivary glands, very small teeth and 
unusual jaw musculature that allows them to chew at something 
ridiculous like 30 bites a second. They are able to harvest termites 
by licking and chewing almost simultaneously but are reported to live 
on a metabolic knife edge. Sloth bears have elongate tongues. Numbats 
have many teeth (more than any other extant marsupial), and also have 
elongate tongues.

When we turn to the dinosaurs that have been proposed as 
insectivores, we see that none of the more important of these 
adaptations are present. Bakker (1986) said 'think tongues', but then 
he would. Tongues can be vaguely reconstructed by looking at hyoid 
bones and muscle scars on the lower jaw, and so far as I know there 
is no indication that any therizinosaur or ornithomimosaur had a 
particularly well developed tongue, nor do any have vertebral or 
sternal modifications to anchor an elongate tongue deep in the body. 
Those that have numerous teeth (therizinosaurs) are apparently too 
large in body size to have subsisted on insects. _Pelecanimimus_ is a 
stumbling block here though, but then how it got numerous tiny 
insects into its mouth is a problem.

Perhaps like humans, chimps and many other animals, some dinosaurs 
did feed opportunistically on termites. 

BTW, has anyone ever wondered how zoos keep anteating animals alive 
and well in captivity? Apparently, pangolins have been fed on minced 
meat mixed with formic acid.

"In the future, the artificial barrier between the paleontologist and 
neontologist will disappear" - - MacFadden, 1992.

DARREN NAISH
darren.naish@port.ac.uk