Thursday, October 28 2010
As a child I was obsessed with fish. I committed scientific names to memory and studied courtship behaviour. I knew the crucial difference between nitrite and nitrate and the benefits and drawbacks of under-gravel filters. At one point around Grade 7, I possessed 300 litres of functioning aquaria.
Because this is the last issue of Farrago and we’re being self-indulgent I thought I would take the initiative to share some details of a certain variety of aquatic denizen that even as a jaded student editor still fascinates me: Lake Malawi Cichlids.
Researchers estimate that there are 800 species of cichlid in Lake Malawi, though only about 300 have been officially described by science. The cichlid population in the lake is one of the best known examples of adaptive radiation, a standard deviation over from Darwin’s finches. All 800 cichlid species in the lake evolved from a single generic ancestor. They inhabit every food and habitat niche in the lake. Some are open-water dwellers and swim miles in search of food. The rock-dwelling varieties known as mbuna spend their entire lives in fiercely guarded rock territories measuring only a few square meters. Some cichlids are herbivores, some are piscivores, one species has even evolved to eat only the eyes of other fish.
Beyond all this, the most remarkable thing about Malawi cichlids is the breathtaking, almost anthropomorphic, level of breeding behavior and parental care they exhibit. They have a unique biological adaptation that resembles fellatio. During courtship the female lays eggs and picks them up with her mouth to secure them from predators. So eager is she to protect her brood that the male is left with no chance to fertilise the eggs. But in her eagerness the female can’t distinguish between real eggs and egg facsimiles. The male has spots on his anal fin that resemble eggs. He swims on his side, displaying these spots and the female tries to pick them up. The male injects sperm into the female’s mouth thereby fertilising the eggs. After the eggs hatch, the parents house their progeny in their mouths, while they fight off other fish, turtles, even otters, to protect their brood.
Recently I watched a documentary on cichlids with a friend. In the middle of an Aulonocara jacobfreibergi courtship ritual he turned to me and said, “Lucas, do you believe in God?” Unsure how to respond, I hesitated. He continued, “because this stuff makes me believe in God. It’s so perfect it can’t be a coincidence.” A reasonable skeptic might equally have his belief in evolution confirmed by the same material. Divine, Darwinian or otherwise, these little fish are something special.F