Koala: Koalas sleep for long periods, in the past people have described them as being 'drugged out' or 'drunk' on gumleaves! However, the koala's sleepy state is due to a slow metabolic rate, an adaptation for handling a diet low in nutrition, and for conserving energy.

An average of eighteen to twenty hours each day are spent resting and sleeping.

-Featherdale Wildlife Park, Sydney