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SOCIAL REPTILES & PACK HUNTING



Brian Franczak has done very well to question some of the aspects of dinosaur
behaviour as so often exemplified in pop-sci art and literature. I know where
you're coming from Brian, keep it up.

It must be emphasised that social hunting embodies a spectrum of behaviours: the
problem with the Bakkerian paradigm is that social theropods have been portrayed
as at one extreme of this spectrum. It is more likely that they lie elsewhere.

Truly sophisticated pack hunting behaviour is indeed a highly complex act where
co-operating members of a clan truly perform in a 'military' style and advance
with a strategy that is dependant on local topography and cover, number and
proximity of other pack members, type and number of prey. The complexity of this
behaviour varies amongst taxa, so much so that 'pack hunting' in the modern
world is a blanket term for diverse strategies. 

 -- Chimps and wolves represent one extreme where individual clan members take
up different stations and act as individuals assigned with a role. True strategy
in a wolf-caribou hunt can be seen in the _Strength in Numbers_ episode of _The
Velvet Claw_, and several good documentaries on chimps have shown them working
to a pre-planned strategy (e.g. some individuals climb up trees well ahead of
the advancing monkeys to block their escape). 

 -- Some populations of orca use strategy: one or more individuals swims
parallel to the beach, distracting the sealions, while other individuals charge
up fast and successfully engage prey. Orca pack hunting with large rorquals as
prey has been recorded and even filmed. Is it not a myth.

 -- Lions effectively operate as individuals during a hunt and the importance
of strategy is arguable. Note that lions (and other felids) take no account of
wind direction whatsoever during hunting. As noted by others on this list,
cheetah and tiger sometimes operate similarly. There is evidence that _Smilodon_
and other extinct taxa did too.

Social hunting also occurs amongst reptiles, but here it is better termed
mobbing. Essentially, predators living in close proximity will join in to defeat
a prey animal. This has been observed in Nile crocodiles and Nile and Komodo
monitors. There is an instance on film where a deer is ambushed by several
Komodo monitors which converge on the animal from all sides and bring it down
together (T. Isles pers. comm.). As the lizards are not operating as a social
unit (they simply happen to be in the same place at the same time), they are not
pack hunting. 

The mobbing of female crocodiles by Nile monitors is well known, and pairs of
monitors are known to apparently work together. Nile crocodiles are well known
to work 'co-operatively' in dismembering carcasses, but they have also been seen
to carry prey items together and may conceivably aid one another in bringing
down prey (Pooley and Gans 1976). Note that Indopacific crocodiles are *highly*
antisocial!

This 'reptilian' part of the social hunting spectrum (also practised by some
birds) may conceivably have been that employed by some extinct archosaurs. It
is unlikely that true carnivoran or chimp-like social hunting was practised by
them (and this includes dromaeosaurids) in view of their cognitive abilities (to
put it politely), but sociality occurring during predatory behaviour seems
likely in view of some death assemblages (Maxwell and Witmer 1996, contra
Howgate pers. comm.). People have to stop thinking that reptiles are somehow
'lower' organisms with dull, ineffectual behaviours.

Yours conservatively..

"Where are my detonators!!"

DARREN NAISH