One unusual feature of Iguanodon is its thumb spike - a horny digit on each hand where you might expect the thumb to be. Palaeontologists are still divided over the function of this spike. Some claim it is for defence and can be used to stab an attacking predator. Other scientists are less sure about its effectiveness as a weapon. Maybe it is used for pulling down branches or digging up plants?
Iguanodontidae Penod Early cretaceous
5 metres (,6.5 feet) £"g<l> 10 metres (33 feet'
Special features Thumb spikes
A good sense oftaste and smell
Iguanodon isn't particularly clever, but studies of its brain show it has very well-developed olfactory lobes, which are the areas of the brain that deal with smells. This means that Iguanodon has a good sense of smell, handy for sniffing out the tastiest plants - or a nearby predator!
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