Sandpoint Reader
Sandpoint Reader
July 29, 2026
By Brenden Bobby
Reader Columnist
At the library’s Citizen Science events, which take place twice a month at the Waterlife Discovery Center on Lakeshore Drive, I love to ask a fun question of guests that really gets the brain buzzing: “What form of life evolved on Earth first? Trees, grasses or sharks?”
People universally guess trees. Plant life is the foundation of terrestrial life on Earth, so it would make sense that trees would have come first.
In fact, sharks have up to 50 million years on trees. The span between the first sharks and the first trees appearing on Earth is about half the time that grasses have been on Earth at all.
In honor of Shark Week, we’re going to take a look at shark’s evolutionary cousins, “batoids,” more commonly known as rays.
Rays split from the ancestors of modern sharks around 200 million years ago, during the late-Jurassic period. They began to develop more powerful pectoral fins than sharks, which made them well suited to skimming the ocean floor to scavenge for food. 
This is commonly seen in rays to this day, as they will often form a frisbee-shaped body that appears to undulate around the edges to propel them through the water. This type of propulsion isn’t unique to rays, as it is also used by cuttlefish — a mollusc related to squids and octopodes. 
It is an especially ancient form of aquatic propulsion that has been used by sea critters such as Dickinsonia, a funky little creature that looked like a ribbed frisbee and inhabited the oceans during the Ediacaran Period up to 560 million years ago. 
These animals are completely unrelated, and their method of propulsion is an example of convergent evolution: A trait that evolves in multiple species independently because it is biomechanically advantageous to do so.
Not all rays travel this way, however. The most well-known example of rays, the manta ray, will actually flap its pectoral fins like a bird flaps its wings to generate lift in water and glide through the ocean. Manta rays, much like many species of shark, need to keep moving in order to breathe. Their movement forces water through their gills, which allows them to breathe, as they lack air-filled bladders like some other forms of fish.
Smaller forms of ray do not require movement in order to breathe. Many species of stingray will bury themselves under seafloor sand and remain stationary for long periods of time. They use spiracles, which act as small tubes of muscle that pull in oxygenated water. This requires energy while at rest, but means the ray can stay stationary to breathe rather than needing to move in order to oxygenate its blood. This is a vital adaptation for smaller rays, which are more likely to be predated by larger animals like sharks.
Stingrays come with a special adaptation that isn’t shared among all rays, and that is the barbed tail for which they are named. Hundreds of people are jabbed by stingrays every year without major complications, but very rarely, a sting can be fatal. This was the case with Steve Irwin, also known as “The Crocodile Hunter,” while he was snorkeling as part of a documentary project on Sept. 4, 2006. It is believed that his shadow startled a massive eight-foot short-tail stingray, which likely believed him to be a predatory tiger shark. It struck hundreds of times in rapid succession, ultimately piercing his heart and ending his life. 
It was a tragic, and extremely rare event, as is the case with many instances of fatalities from sharks and their evolutionary cousins.
There are an estimated five to 10 fatal shark attacks per year, while one to two people die from stingrays per year. If that’s scary, put into perspective that humans intentionally kill up to 73 million sharks per year, with up to another 70 million being killed as accidental bycatching during fishing operations. 
Most sharks and all rays will actually ignore humans entirely unless provoked. Only three species of shark are known for committing unprovoked attacks on humans: the great white, the tiger shark and bull shark. While one could argue that Steve Irwin’s death was an unprovoked incident, he was still close enough to the animal in its own territory to be struck by its tail, and all experts that have evaluated the incident seem to agree that it was an act of self-defense. If I lived in the neighborhood of tiger sharks, I’d probably be a little jumpy, too. 
Have you ever visited a large aquarium and had the opportunity to pet stingrays? You might not know that the aquariums will trim the barbs of the rays to avoid guest injury. These rays are also regularly exposed to human contact, and so long as guests follow procedure and don’t harm or agitate the ray, they are likely to continue allowing humans to pet them. 
If you have encountered a ray in an aquarium petting pool, you may have noticed that they’re a little slimy. This is true of every ray, which have a built-in mucus barrier that acts like an extra layer of skin. Our own skin exists as a wall between external bacteria and our internal organs, tissues and blood. Our blood will seep out and fill gaps in our skin when it is damaged to block bacteria from getting in. A ray’s mucus barrier does something similar, while also reducing drag and allowing them to glide through the water with less resistance.
In many ways, this acts similarly to an ocean swimmer coating their skin in petroleum jelly. The petroleum acts as a lubricant and barrier that keeps nasty things, including jellyfish stings, out while also slightly reducing drag in the water.
We didn’t evolve to exist in the ocean, so Vaseline won’t help us quite as much as a ray’s mucus will help them.
Stay curious, 7B.

The Sandpoint Reader is our town’s local, independent weekly newspaper. “Independent” means that the Reader is locally owned and operated by people who were born and raised in Sandpoint. The Reader is owned by Publisher Ben Olson, Editor-in-Chief Zach Hagadone and Senior Writer Soncirey Mitchell. Sandpoint Reader LLC is a completely independent business unit; no big newspaper group or corporate conglomerate or billionaire owner dictates our editorial policy. And we want the news, opinion and lifestyle stories we report to be freely available to all interested readers – so unlike many other newspapers and media websites, we have NO PAYWALL on our website. The Reader relies wholly on the support of our valued advertisers, as well as readers who voluntarily contribute. Want to ensure that local, independent journalism survives in our town? You can help support the Reader for as little as $1.
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Filmmaker Jimmy Matlosz of the Idaho Film Company has made a series of mini documentaries about influential Sandpoint locals, including the late Dann Hall and  Erik Daarstad as well as icons Diane Michaels and Dan Shook. He is currently working on a series of interviews connected to the history of the Panida Theater.  Jimmy is a 30-year veteran filmmaker who’s work can be seen at dpmatlosz.com.
Ever wonder who makes the Reader happen? Here’s a behind-the-scenes look pieced together by summer 2017 intern McCalee Cain in which Ben, Cameron and Lyndsie explain what exactly about the Reader keeps them coming back to their shabby (but well–loved) office each week.
The Sandpoint Reader is our town’s local, independent weekly newspaper. “Independent” means that the Reader is locally owned and operated by people who were born and raised in Sandpoint. The Reader is owned by Publisher Ben Olson, Editor-in-Chief Zach Hagadone and Senior Writer Soncirey Mitchell. Sandpoint Reader LLC is a completely independent business unit; no big newspaper group or corporate conglomerate or billionaire owner dictates our editorial policy. And we want the news, opinion and lifestyle stories we report to be freely available to all interested readers – so unlike many other newspapers and media websites, we have NO PAYWALL on our website. The Reader relies wholly on the support of our valued advertisers, as well as readers who voluntarily contribute. Want to ensure that local, independent journalism survives in our town? You can help support the Reader for as little as $1.
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