For example , among the cichlid Cyrtocara eucinostomus in Lake Malawi , up to 50,000 large and colourful males display together on a lek four kilometres long .
Based on these displays , each female then selects the male they want to be their mate .
Among the cichlid Cyrtocara eucinostomus in Lake Malawi , up to 50,000 large and colourful males display together on a lek four kilometres long .
Based on these displays , each female then selects the male they want to be their mate .