There are some interesting wooing strategies in the animal world. Extravagant dances, bright colors and loud calls.
But lady tilapia don’t want any of that – they’re looking for a male with great urine.
Males will dig a nest in the sand, defend their territory, and then pee a lot. If they’re lucky, they’ll catch the attention of a female passing by.
"It's actually a quite interesting fish, because tilapias are highly social animals, so the males form hierarchies in a so-called spawning arena," Tina Keller-Costa, of the Centre of Marine Sciences at the University of Algarve in Portugal told National Geographic.
The more dominant males have more pheromones, which are released as they urinate. Females will follow the pheromone trail to their beloved. The most attractive males have larger bladders and bigger muscles “down there” – so they can control their pee.
Inferior males aren’t so lucky. They have smaller bladders so they can’t store their urine while dominant males, Keller-Costa adds, "can extend the bladder, and that enables them to hold on to larger urine quantities. When they're facing a female or when they're facing a competitor, they're literally, actively squeezing it all out."
It’s pretty clear who has the competitive advantage there.
The urine also preps females for mating by triggering hormones that will ripen her eggs. That way, males can time the release of their sperm with the release of eggs and ensure they fertilize as many eggs as possible since fertilization happens in the water, not in the female. Males don’t want another guys’ sperm getting in on their egg party.