Did you know??? It has been estimated that up to 33% of black swans are homosexual and that nearly 25% of all black swan couples are same-sex couples. These couples are almost always two males getting together. These males sometimes steal a nest from a heterosexual couple and raise the young as their own or one male copulates with a female and once she has laid her eggs they chase her away and raise the chicks themselves. Scientists believe there is a biological advantage in this behaviour as it appears that there is a higher survival rate amongst cygnets (chicks) raised by male-male couples than by male-female pairs. This may be due to the fact that there is an additional male to protect them and that having chosen to be parents they are more caring than natural heterosexual pairs.