A study by the University of Queensland has found that dark coloured male giraffes are more solitary and less social than their lighter-coloured counterparts. 

The study’s lead author, Dr Madeleine Castles, said the colour may display the males’ physical conditions and is a sign of competitive ability to others.

"Colour could be linked to testosterone, to heat stress, diet, genetics or a combination of multiple factors," Dr Castles said. 

Dr Castles said the darker male giraffes are more dominant and are preferred by females.