530 million years ago the very first fish appeared in Earth’s oceans. They were quite different to modern fish, having cartilage instead of bone, no fins and round, constantly open mouths. Most of these either became extinct or evolved into modern fish. But there is a type of fish still around today that closely resembles its ancient ancestors – the lamprey.
You would be forgiven for not knowing much about lampreys – I myself hadn’t heard of them at all until a few years ago. But fear not, here’s a list of facts on these strange, leechlike fish, courtesy of Education Quizzes:
- There are 38 different species of lamprey. Some are parasites which suck the blood of their hosts while others are filter feeders
- Most are about 30cm long but some can grow up to half a metre in length
- Lampreys have large, round mouths filled with several rows of teeth. They can look quite horrific in close-up!
- Lampreys spend most of their lives in freshwater rivers and lakes. When they are 10 years old or so, they leave their homes and go out to sea
- They spend a couple of years as adults living in the salty sea, before returning back to their homes in order to spawn
- During their long travels, lampreys often rest by attaching themselves to rocks by sucking on them. This is the origin of their name which, in Latin, means stone licker
- After returning to the spawning ground (always in springtime) the female lamprey makes a nest where she will lay as many as 100,000 eggs
- Male lampreys fertilise the eggs. After this happens, males and females alike both die
- They lay so many eggs because very few will make it to become adults. Lamprey eggs and larvae are a source of food for many other creatures
- Lampreys were a favourite food of the upper classes in the Middle Ages. Henry I was said to have died from eating too many of them!
- Nowadays they are more commonly used as bait by fishermen although they are still considered a delicacy in some countries
Though they are not yet under threat, lamprey numbers have declined considerably. At the time of the Norman Conquest (11th Century) they were common in England’s rivers but due to the building of dams and industrial pollution, they are now much rarer. In North America however, they have become a pest. They managed to find their way into the Great Lakes via manmade canals and now they are becoming a threat to the natural ecosystems there. Yet another example of mankind messing with nature with unforeseen consequences.