Wild animals use a variety of methods to communicate with each other.  Visual displays and vocalisations require the recipient animal to be nearby to be effective, but there are more subtle (to us) signs that are used as well that are effective after the sender has left, and may remain effective for days or even weeks.  Much information can be passed between animals, such as the age, sex and status of the “sender”.  The animal receiving the signal can then make decisions about whether to proceed into another animal’s territory; whether there’s a receptive female nearby; and so on.

Scent marking or olfactory communication is used by many animals, some which you might not think about.  The next time that your cat rubs its face against you, remember that it’s actually scent-marking you, not just being cuddly!  Chemicals in dung and urine may contain important information about the age, sex and condition of the animal.  For example, dominant rhino bulls spray urine and scrape at dung middens to show their dominance and spread the scent over a larger area.  Many species have scent glands on the feet, head and around the anus as well.

The photo shows a male warthog marking a tree with his tusk glands.  He is probably marking to let other mature hogs know that it’s his territory and he’s been there recently.