Re: Venomous (should be septic) Theropod Biting

["Darren Tanke" <dtanke@dns.magtech.ab.ca>]

 I've been an occasional "lurker" on this list and came across the
discussion about theropod dinosaurs possibly having a poisonous or venomous
bite (Darren Naish, this list, Nov. 10, 98). As Philip Currie has recently
co-authored a paper with me, (which is, I believe is currently "in press"
(GAIA- Theropod Paleobiology Volume)) and which partly addresses an aspect
of this topic, I thought I would add my views here.

 1. Poisonous bite. I don't belive that there is any good evidence for a
true venomous or poisonous bite in any theropod, at least any theropods
recovered so far. By this I mean whereby the theropod bites its prey once or
twice, injects or introduces a toxic substance, "poisons" the prey which
collapses and dies a relatively short time later (ie. a poisonous snake
bite). However, the possibility of a SEPTIC bite is very real. Any animal
today has a mouth full of bacteria, and if it engages in inter- or
intraspecific biting, pathogens can readily be transmitted. Just think of
the automatic rabies fear and rigorous medical treatment provided when
someone is bitten by a dog. The serrations of theropod dinosaur teeth would
have served as areas for entrapment of meat fibres during feeding (see
Abler, W.L. 1992. The Serrated Teeth of Tyrannosaurid Dinosaurs, and Biting
Structures in Other Animals. Paleobiology, 18(2):161-183). Abler showed how
meat fibres could become entrapped at the base of each serration. These
would decay, resulting in numerous bacteria. This paper may be one of the
ones that inspired the "poisonous bite" hypotheses for theropods. The GAIA
article we submitted (Tanke, D.H. and Currie, P.J. Head-Biting in Theropod
Dinosaurs: Paleopathological Evidence. GAIA, in press), addresses
intraspecific (same species) fighting and biting behavior in several
families of large theropods (SINRAPTOR, MONOLOPHOSAURUS, tyrannosaurids). We
documented relatively common occurrences (44%) of healing bite trauma on the
head in several species of Late Cretaceous tyrannosaurids from
Campanian-aged deposits of Alberta, Canada. The cranial lesions (wounds),
look exactly like unhealed tyrannosaurid bite marks on prey (hadrosaur,
ceratopsian) bone, but with one important difference- there is some degree
of healing. So tyrannosaurids DID bite each other. Nothing else was around
at the same time that was big (or brave) enough to do this biting. 
 There is good evidence that tyrannosaurids scavenged carcasses. I've spent
11 field seasons in ceratopsian mass mortality bonebeds in Alberta, and can
say in most cases, the second most common find in these sites are large and
small theropod teeth showing resorbed roots and no abrasion from fluvial
transport. A hadrosaur mass mortality bonebed being excavated near our
museum also shows this. It seems then, one can make a compelling arguement
that these teeth are in fact from the theropods scavenging carcasses on
site. In the warm, humid environment that was Alberta back then, dinosaur
carcasses would have quickly decayed. Ingestion of such carrion and the
absence of dental hygiene [ a point one cannot argue :) ], a tyrannosaurid's
(or any theropod's for that matter) mouth would have been a most interesting
microbial environment indeed! If such a creature then landed an immediately
non-fatal, but SEPTIC bite on a conspecific, the latter could escape and
then later on develop a blood infection and/or osteomyelitis (bone
infection) at or near the traumatized (ie. toothmarked) sites and
contributing to its death. And this is precisely what we are seeing in the
SINRAPTOR and Albertan tyrannosaurid specimens. An immediately non-fatal
bite received by a tyrannosaurid conspecific was as good as a death sentence
in most cases. These animals were bitten, got away, developed bone
infections and died a relatively short time after being bitten. How short a
time I don't know, as healing rates in dinosaurs is only now beginning to be
investigated. However, the fact that the depression of the tooth strike
against bone is usually still present, implies the wounds are only just in
the beginning or early stages of repair. If a tyrannosaur were to bite a
prey item which was able to somehow escape, a similar process of blood/bone
infection could ensue leading to death. Perhaps all this has been
misconstrued as a poisonous or venomous bite. It reality such events should
be called a SEPTIC bite.

 Anyone interested in the SINRAPTOR facebite story should go to my homepage
(see URL in sig.file below) and click on the link at the bottom: "About The
Fighting Dinosaurs". There you will find a short story and drawing showing
the pattern of distribution of healing bite marks on the Sinraptor's head,
and a short bibliography. This poor guy suffered no less than 25 wounds
caused by the puncturing and raking teeth of a presumed rival. I'm presently
preparing a virtually complete subadult DASPLETOSAURUS skull that shows even
more healing bite wounds, including one that shows how a tooth has crunched
down across the bridge of the nose (dorsal nasal/premaxilla suture region).
But that's another story (and another paper in progress). Tyrannosaurs truly
were nasty animals.

 2. Dr. Livingstone/Lion bite. In compiling my paleopathology bibliography
(again see my homepage for details of this project), some years ago I came
across an article (sorry, citation not handy now) discussing the role of
shock and its numbing effects on the injured victim. The article went on to
describe how people can be injured and not even know it (ie. feel pain)
until: 1. they see the wound, or, 2. initial shock of being attacked/injured
wears off. The article went on to describe the attack on Livingstone. His
apparent lack of pain during and immediately after being attacked was
attributed to either shock, or something akin to simply being "numbed by
fear". It has been observed that when some [lucky] soldiers in night battle
have had their water canteen shot through, when they felt the water
trickling down their leg/groin, they "knew" they'd suffered a bullet wound
and even felt "pain". Clearly, some psychological effects must also come
into play regarding the numbing/pain effect from injuries. The article also
went on to say that some people DID feel intense pain during similar Lion
attacks, so the pain response issue can be variable. 

 I'd be interested in learning more about the Bakker Earth article and
Graeme Dinoworld article mentioned in Naish's posting. Citations please!
Citations of any other articles regarding venomous/poisonous bites/biting in
dinosaurs would also be welcomed.

 Darren Tanke
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FAEVUS QUAESITOR SCIENTIA                                  FODERE AUT CADERE

DARREN TANKE, Technician I, Dinosaur Research Program, ROYAL TYRRELL MUSEUM
OF PALAEONTOLOGY, Box 7500, Drumheller, Alberta, CANADA  T0J 0Y0 and:

Senior editor of: Annotated Bibliography of Paleopathology, Dento-Osteopathy
and Related Topics. 12,542 citations as of July 26, 1998.
For details, visit the bibliography homepage at: http://dns.magtech.ab.ca/dtanke
Can you help (translations, photocopying or financial support) with this
ongoing project? Email me at: dtanke@dns.magtech.ab.ca
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