many minutes later. Furthermore, the loris’s teeth,
though sharp and effective at penetrating flesh, are fairly
typical for mammals which share its omnivorous diet,
and thus are probably not specialised for the purpose of
envenomation. And while there is at least one reported
fatality from a slow loris bite, the responsible toxins are
essentially allergens, the same type as those expressed
by cats, and therefore exert limited toxic effect unless
the victim has an anaphylactic reaction. To further
complicate matters, the loris will also spread the exudate
throughout its fur as a poisonous deterrent to ectopara-
sites and predators.
So, toxic secretion via specialised glands? Strictly, yes.
Administered through the infliction of a wound? Partly,
yes. Via a specialised delivery mechanism? Maybe.
Venomous? Probably. Examples like these have led
researchers - toxinologists, in particular – to broaden the
definition of venom slightly by omitting the requisite for
a specialised delivery system. When evaluating cases
such as these, it is important to remember that evolution
is a continuum. It is probably easier than you think to find
examples of extant species which exist at stages all along
the continuum from non-venomous to venomous, and
perhaps the slow loris is one of them. So, at what point
on this continuum do we actually class something as
venomous? Good question. And how, then, does the
composition of the toxic secretion come into play here?
What actually is venom?
A complex cocktail.
Venom is, very simply speaking, a complex mixture of
bioactive proteins and peptides. While there are also non
-proteinaceous molecules in venoms, little is known
about their specific function and it is thought that most
of them perform some kind of housekeeping role.
However, as this is not necessarily always the case, to be
a bit more accurate we generally refer to the bioactive
constituents of venom as toxins: molecules which can
induce a toxic effect.
Molecular size and structure often differ categorically
between a venom toxin and a poison toxin. Biological
poisons are typically very small, organic molecules - that
is, they are not usually proteinaceous - and their toxic
effects can be experienced following ingestion, absorp-
tion, or inhalation of the poisonous substance. Venom
toxins are usually comparatively large proteins whose
activity relies on their structural integrity, which exposes
active sites on the molecule. However, this also makes
them fairly unstable. Any significant changes to structure
- by heat, for example - results in a loss of toxin activity.
This is called denaturation, and explains why the first aid
treatment for a stingray sting is to immerse the affected