[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: AW: Heterodontosaurid with protofeathers
Quoting Amtoine Grant <email@example.com>:
> They also COULD be venemous,
> something we'll probably never know for sure. YOU WOULD think that a
> group of warmer-than-usual-blooded reptiles that diversified so much
> over approx. 140 million years would produce at least a FEW poisonous
"Poisonous' and 'venomous' are two different things. As I understand it, vemon
is usually only toxic
when it enters the blood stream, while poison can kill by being injested.
That's why you can drink
snake venom, and your digestive juices will break it down harmlessly (hence why
snakes can eat
animals they've envenomated). Having an open wound in your mouth, throat or
make it a dangerous practice though.
There are a few species of poisonous extant birds, but no venomous ones. In
contrast, there are
only two venomous mammals that I can think of (the platypus and Solenodon), but
I'm not sure
there are any poisonous mammals.
It's much easier for an animal to evolve to be poisonous to some degree than to
venomous. Venom not only requires a toxin, but also an injection system. Venom
injected via a deliberate act (biting, or pricking with a spur), which requires
behavioural changes as
well as the complex structural relationship between venom gland and delivery
Poison however can be accumulated from eating toxic food (poison arrow frogs,
and probably the
poisonous birds) or by exuding toxins from glands in the skin (cane toads).
Most poisons are a
passive defense that prevents the animal from being eaten. There is certainly
predator that I know of that deliberately throws itself into the mouths of it's
GIS / Archaeologist http://geo_cities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com