CLEVER VENOM
How predators use chemicals to kill
The venom of a sea wasp punctures the blood cells of its prey, and the black mamba's makes your heart collapse. But venom is more than just a killer. Using DNA analysis, scientists have mapped the origin of venom and its importance for animal life throughout the eons. The conclusion is crystal clear: Venom has given far more life than it has taken.
The enthusiasm was evident in a laboratory at the institute for evolutionary studies in the SouthAfrican city of Johannesburg in early 2017. A small team of biologists and fossil experts from the University of the Witwatersrand had just concluded a CT scan of two rare fossilized skulls from the prehistoric animal Euchambersia mirabilis, a mammal-like reptile the size of a small dog, which lived 260 m years ago.
The scanning results of a strange depression just above the upper jaw have been run through a computer program, which has reconstructed the missing parts of the skull. And the result at the computer screen shows that the depression was rather a hollow filled by a gland. But not just a salivary gland. The size and a direct connection to the animal’s mouth indicate that the gland used to produce venom. The two types of glands are very similar: Both produce liquid, which contains proteins and salts, but where the salivary glands produce harmless proteins to digest meals, the venom glands produce small proteins called peptides with lethal characteristics, which can short-circuit a nervous system or create bleeding to serious that the organs shut down.
The discovery of the world’s oldest venomous land-based vertebrate does not have much to do with death. Rather, the find of venom in yet another species, which lived several hundred million years ago, confirms an evolutionary view of venom as one of the major life-givers in the animal kingdom – without venom, biodiversity would not have evolved into being so varied as it is today.
VENOM GIVES LIFE TO ANIMALS AND ECOSYSTEMS
Initially, the scientists were surprised by the fact that the evolution of venom in vertebrates – animals with a spine like mammals and reptiles – had to be moved all the way back to the time before the first venomous snakes slid across the surface of Earth 160 m years ago. But actually, it makes sense. Venom has armed the vertebrates for the evolutionary battlefield and has given them an advantage in the great battle for survival. The deadly cocktails have, on the one hand, helped predators to kill their prey