12 Things You Should Know About Rattlesnakes

johnaudrey, iStock/Getty Images Plus
johnaudrey, iStock/Getty Images Plus

Coiled defensively, its head reared and tail vibrating, a threatened rattlesnake commands respect. These venomous serpents have evolved one of nature’s most dramatic warning systems in their signature segmented rattles. But as we’ll see, their powerful bites are not the only thing rattlesnakes have going for them.

1. Rattlesnake scientific names refer to musical instruments.

All 36 species of rattlesnake are native to the Americas, with an overall range stretching from southern Canada to central Argentina and concentrated in the American Southwest. They can survive in all kinds of habitats where their prey—birds, rodents, amphibians, and other small animals—is plentiful. Rattlesnakes belong to two genera in the subfamily Crotalinae (the pit vipers): Crotalus, from the Greek word for castanet; and Sistrurus, invoking an ancient Egyptian musical instrument. Both genus names undoubtedly refer to the snakes’ characteristic rattles.

2. Venoms in rattlesnake bites are highly variable—even among members of the same species.

Each type of rattlesnake bite venom out there is an intricate cocktail loaded with different enzymes, toxins, and other compounds. Hemotoxins, which break down capillary walls and hinder blood circulation, are key ingredients in most of them. Neurotoxins, which attack the victim’s nervous system and cause seizures or paralysis, are another weapon. Venom composition can be extremely variable among individuals of the same species; for example, some timber rattlesnakes living in the American South have more neurotoxic venom than their northern counterparts do.

3. Rattlesnakes bite with movable fangs.

Cobras, mambas, and other snakes inject their venom into their victims through a pair of proteroglyphous, or fixed, fangs near the front of their mouths. Those snakes have to bite down and hang on to their prey to deliver the venomous punch. Rattlesnakes take a different approach. Like copperheads and Old World vipers, they have solenoglyphous fangs, which can actually swing forward and allow the rattlers to strike quickly, inject venom, and then back off. When the fangs aren’t being used, they’re pulled back and pressed against the roof of the snakes’ mouths.

4. Most rattlesnake bites are not fatal.

Rattlesnakes are the leading purveyor of venomous snakebites in North America. About 7000 to 8000 people are bitten each year, but thanks to effective antivenins, only five or six bites prove fatal.

5. Disembodied rattlesnake heads can still bite.

In 2018, a man in Corpus Christi, Texas found a western diamondback rattlesnake in his backyard and decapitated it with a shovel. Imagine his surprise when the head bit him on the hand. The man lived, but there have been cases of detached heads fatally envenomating people; the biting reflex in many venomous snakes remains active after the animal’s death.

6. The eastern diamondback rattlesnake is the largest venomous snake in North America.

Native to the southeastern U.S., the eastern diamondback can grow nearly 8 feet long and weigh more than 15 pounds. It’s the largest rattlesnake on Earth and the biggest venomous snake on the North American continent.

7. Rattlesnakes start growing rattles after their first shed.

Each rattlesnake is born with a nubby scale at the tip of its tail called a pre-button. After the snake’s first shed of their skin, the pre-button gets replaced with a button, a larger, hourglass-shaped scale. Later sheds add hollow, interlocking segments of keratin to the end of the tail. By vibrating the segments, the snakes create its distinctive rattling noise. Although it’s a myth that rattlesnakes must vibrate their tails before striking, they do use their rattles to warn approaching animals or people.

8. The number of rattle segments has nothing to do with the rattlesnake’s age.

A popular myth suggests that each rattle section represents a year in the animal’s life. In reality, a rattlesnake can shed multiple times, and gain multiple rattle segments, in a single year. Segments can also wear down and break off over time.

9. Rattlesnakes don’t lay eggs.

Like anacondas, rattlesnakes are ovoviviparous: They produce eggs that hatch inside their bodies and give birth to live, fully formed young. Depending on the species, a rattlesnake litter can include anywhere from one to 25 infants.

10. Not every rattlesnake species has a rattle.

Crotalus catalinensis, the Santa Catalina rattlesnake, has evolved to be rattle-free. It lives on Isla Santa Catalina, a small island in the Gulf of California. Although it belongs to the same genus as diamondbacks and timber rattlers, the snakes’ ancestors may have lost their appendages because there are fewer predators and big, trample-y mammals on the island to warn with menacing noises.

11. Rattlesnakes help plants by distributing seeds.

In a 2018 study, researchers looked into the guts of 50 dead rattlesnakes preserved at museums. They found 971 plant seeds that were likely carried by the rodents the snakes had eaten. When a rattlesnake devours some hapless mouse, the seeds it carried in its cheek pouches make their way through the snake’s digestive tract intact. By pooping out the seeds, the snakes help to restore plant growth in its habitat.

12. Benjamin Franklin admired timber rattlers.

Benjamin Franklin thought that rattlesnakes embodied uniquely American diplomacy and toughness. “She never wounds till she has generously given notice, even to her enemy, and cautioned him against the danger of stepping on her,” he wrote in a Pennsylvania newspaper in 1775. “Was I wrong, Sir, in thinking this a strong picture of the temper and conduct of America?”

He also noted that, like all snakes, timber rattlers don’t have eyelids, which made them naturally watchful. “She may therefore be esteemed an emblem of vigilance,” Franklin wrote.

Rattlesnakes later became symbols of America’s war for independence. Christopher Gadsden, a colonel from South Carolina, designed a personal flag to be flown on five ships belonging to the Continental Army. The bright yellow banner sported a coiled rattlesnake emblem and the caption “Don’t Tread on Me.” It remains popular among advocates of smaller federal government today.

The Horrors of Anglerfish Mating

Masaki Miya et al. "Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective," BMC Evolutionary Biology 10, article number: 58 (2010), Wikimedia Commons // CC BY 2.0
Masaki Miya et al. "Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective," BMC Evolutionary Biology 10, article number: 58 (2010), Wikimedia Commons // CC BY 2.0

When you think of an anglerfish, you probably think of something like the creature above: Big mouth. Gnarly teeth. Lure bobbing from its head. Endless nightmares. 

During the 19th century, when scientists began to discover, describe, and classify anglerfish from a particular branch of the anglerfish family tree—the suborder Ceratioidei—that’s what they thought of, too. The problem was that they were only seeing half the picture. The specimens that they were working with were all female, and they had no idea where the males were or what they looked like. Researchers sometimes found some other fish that seemed to be related based on their body structure, but they lacked the fearsome maw and lure typical of ceratioids and were much smaller—sometimes only as long as 6 or 7 millimeters—and got placed into separate taxonomic groups.

It wasn’t until the 1920s—almost a full century after the first ceratioid was entered into the scientific record—that things started to become a little clearer. In 1922, Icelandic biologist Bjarni Saemundsson discovered a female ceratioid with two of these smaller fish attached to her belly by their snouts. He assumed it was a mother and her babies, but was puzzled by the arrangement.

“I can form no idea of how, or when, the larvae, or young, become attached to the mother. I cannot believe that the male fastens the egg to the female,” he wrote. “This remains a puzzle for some future researchers to solve.”

When Saemundsson kicked the problem down the road, it was Charles Tate Regan, working at the British Museum of Natural History in 1924, who picked it up. Regan also found a smaller fish attached to a female ceratioid. When he dissected it, he realized it wasn’t a different species or the female angler’s child. It was her mate.

The “missing” males had been there all along, just unrecognized and misclassified, and Regan and other scientists, like Norwegian zoologist Albert Eide Parr, soon figured out why the male ceratioids looked so different. They don’t need lures or big mouths and teeth because they don’t hunt, and they don’t hunt because they have the females. The ceratioid male, Regan wrote, is “merely an appendage of the female, and entirely dependent on her for nutrition.” In other words, a parasite.

When ceratioid males go looking for love, they follow a species-specific pheromone to a female, who will often aid their search further by flashing her bioluminescent lure. Once the male finds a suitable mate, he bites into her belly and latches on until his body fuses with hers. Their skin joins together, and so do their blood vessels, which allows the male to take all the nutrients he needs from his host/mate’s blood. The two fish essentially become one.

With his body attached to hers like this, the male doesn't have to trouble himself with things like seeing or swimming or eating like a normal fish. The body parts he doesn’t need anymore—eyes, fins, and some internal organs—atrophy, degenerate, and wither away, until he’s little more than a lump of flesh hanging from the female, taking food from her and providing sperm whenever she’s ready to spawn.

Extreme size differences between the sexes and parasitic mating aren’t found in all anglerfish. Throughout the other suborders, there are males that are free-swimming their whole lives, that can hunt on their own and that only attach to the females temporarily to reproduce before moving along. For deep-sea ceratioids that might only rarely bump into each other in the abyss, though, the weird mating ritual is a necessary adaptation to keep mates close at hand and ensure that there will always be more little anglerfish. And for us, it’s something to both marvel and cringe at, a reminder that the natural world is often as strange as any fiction we can imagine.

Naturalist William Beebe put it nicely in 1938, writing, “But to be driven by impelling odor headlong upon a mate so gigantic, in such immense and forbidding darkness, and willfully eat a hole in her soft side, to feel the gradually increasing transfusion of her blood through one’s veins, to lose everything that marked one as other than a worm, to become a brainless, senseless thing that was a fish—this is sheer fiction, beyond all belief unless we have seen the proof of it.”

This Automatic Fetch Machine Will Keep Your Dog Occupied When You Don't Have Time to Play

iFetch
iFetch

Every dog owner knows that it's impossible to keep up with a pooch that's always looking to play. But if you want to keep them active while still having time for yourself, there's the iFetch, a toy that will automatically throw tennis balls, allowing your canine to play fetch whenever they please.

You can find the iFetch Original, which is ideal for small or medium dogs, on Amazon for $115. The Original can either be charged with an AC adapter or run on six C batteries, both of which are included. You can adjust the settings on the iFetch to throw the ball 10, 20, or 30 feet, making it perfect for indoor or outdoor play. Once it's charged and the distance is set, let your canine drop a tennis ball into the machine and it will take care of the rest.

If you have a large dog, look for the iFetch Too, which is available on Amazon for $200. This model has a rechargeable battery that can last up to 300 throws. This model can launch the ball 10, 24, or 40 feet, and it also comes with a custom option, so you’ll find room for your dog to play no matter how much space is available.

If your dog loves their new toy, but you don't love finding slobbery tennis balls around the house, check out the company’s medium- and small-size slobber-proof balls.

It may take time for your canine to learn how to use the toy, but the company has some training tips from Nicole Ellis, a certified professional dog trainer. To start, it's recommended that your dog knows the “drop it” command. If they don’t, check out their training tips here. After your dog has mastered that command, the company has plenty of tricks, such as keeping training sessions short and ending them on a positive note. For more ideas, check out their page.

Once you set up your iFetch and watch your furry friend run back and forth, you may start to wonder why they like fetch so much. According to research on the subject, when dogs exercise, neurotransmitters stimulate reward regions in their brain, which is much like when humans experience a "runner's high."

If you happen to notice your canine seems particularly athletic while they are chasing the ball back and forth, check out these other sports they can play.

Mental Floss has affiliate relationships with certain retailers and may receive a small percentage of any sale. But we choose all products independently and only get commission on items you buy and don't return, so we're only happy if you're happy. Thanks for helping us pay the bills!

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