Attracting and keeping a mate is not that easy, as many young lovers will affirm.
For many animals it is all down to the males to battle it out and show off to attract females, often at great cost to themselves.
At the end of the October rut, red deer stags are exhausted, underweight and often injured.
In some species it is a free for all, garter snakes in Canada have mass orgies when spring arrives but some male snakes may find that the female they are trying to mate with is actually a cross-dresser!
And the females? Well, even if they have matings forced on them, many species can select the sperm they want to use inside their bodies, rejecting - even ejecting - the sperm of undesirables.
A trick even the humble chicken can perform to perfection.