I have long been frustrated with how many shark dives I have been on where the same facts about sharks are regurgitated often, some are anecdotally true because of some personal experience. As an animal health professional (veterinary technician specializing in exotic animal care) and a lifelong passionate learner of animals’ natural history, I am triggered by how to lay a lot of the information people often spew and often from dive professionals. So, I set out to try to find and read every academic textbook or article I could find. That is what led me to find Peter Klimley” ‘s Biology of Sharks and Rays.
I don’t take this pursuit lightly before starting to read any shark textbook, so I thought I should start with the general marine biology textbook. So I read Marine Biology by Peter Castro and Micheal Huber, which, to my great delight, was one of the best books I read in 2022. After reading Emporos of the Deep and Chasing Shadows, a few names kept popping up of people who have dedicated their lives to learning more about sharks, and Peter Klimley’s Biology of Sharks and Rays was the first one i could get my hands on.
Biology of Sharks and Rays comprises 16 chapters, humbly covering what we know about sharks and rays up to 2013. The book summarizes how the researchers came up with the studies and how they were validated. As a diver, I found this book to have a tone of enlightening information about sharks, which shed light and many of the behaviours I have experienced on shark’s dives. The uniqueness of each species makes what we don’t know about sharks overwhelming as one can cross over very little information from each species, things such as how and why Bull sharks breed in fresh water and how they are able to tolerate it as fresh water normally kills most other species. I was also blown away by how varied sharks are in how they give birth. There are shark species that lay eggs outside their bodies, leaving eggs in grasses and in kelps or attaching them to rocks. Then other species form eggs inside of themselves where each embryo has its own independent sack that has everything it needs till birth, or as I came it find out about the sand tiger shark, when the internal egg runs out of nutrients, normally they break out and eat there litter mates in the womb. The most fascinating to me was how some species of sharks, which are considered more evolved, like mammals, form placentas, and the mother continually feeds the infant shark in the womb. If one stops and thinks about the shark, which would have to go through a first trimester growing a placenta to raise its baby. Do mother sharks experience morning sickness? (I am a new father as of 2023, so I am still reeling from the whole experience.
Another chapter on territory and ranges really helped me understand why on every dive on my last trip to the Bahamas on Black Beard Cruises, click here to read my review. We always had sharks around even when we weren’t feeding them as part of a shark dive. I learned that many reef shark species will have home reefs or territories where they will spend the bulk of their day patrolling for injured species and communicating with 3-5 other sharks in the same territory. When there is a feeding frenzy in a neighbouring territory, they will go over to check out what the commotion is and see if there is a meal to be had, but once the action is done, they swim back to the home territory. This will change how I dive on reef dives I want to make a greater effort to identify the individual so when I revisit the site, I can confirm that they are the same animals. This also helps reinforce when we should only take pictures and leave bubbles. Destroying or mucking with the underwater environment is just like vandalizing their home and may have a wider impact that we aren’t aware of.
Another chapter on sharks’ sense of smell will blow your mind about how sensitive sharks are, but blood isn’t what they smell like most shark week would lead you to believe, I would spoil the surprise about how sensitive and what actually attracts sharks. Very interesting how this study was built and how even the military assisted in this research because the range sharks could smell was blowing everyone away.
One thing I love about this textbook and textbooks in general is how transparent they are with how we learnt this information, how studies are compiled and, more importantly. How transparent scienties are about what they don’t know, which is a lot more than what we know at this point. Sometimes the general public will receive scientists’ excitement when they learn something new or have a “discovery” that could come off as hubris. In actual fact, it is normally excitments that there are fruits to their labours, and often the data will show something that nobody expected.
Needless to say, The Biology of Sharks and Rays is only the first academic text book I have read on sharks, but it gets the best book I read in 2023! I would highly recommend