Hierarchical animals have what is known colloquially as a 'pecking order'. Animals at the top of the hierarchy aggressively dominate those lower down the ranks in order to retain privileged access to resources such as food, mates or a safe places to sleep. Males are often likely to dominate a pack, but there are some exceptions, as in spotted hyenas where females outrank males. In other cases there may be an alpha female in addition to an alpha male, as in wolves where she is the only one that will bear pups.

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