Shark Spotlight: Sandtiger Sharks

It’s that time of year again—Fin Fest! Sharks are already on our minds 24/7, but this week-long celebration of sharks (July 22 – 29, 2018) gives us an excuse to really show how much we appreciate these jaw-some animals.

Of the three shark species in the Shark Gallery, sandtiger sharks are often the first ones you notice and the ones you remember long after you visit for a number of reasons. They tend to cruise around near the water’s surface, positioning themselves above the nurse and sandbar sharks at the top of the gallery’s vertical hierarchy. The aesthetics, too, are enough to drop a few jaws. Row upon row of ragged, razor-sharp teeth reveal themselves even while the shark’s mouth is at rest, lending an aggressive edge to an already imposing body that can grow to 10½ feet and more than 350 pounds.

However, the voracious behavior implied by these fearsome features couldn’t be further from the truth. In fact, sandtiger sharks are a very docile species known to attack humans only when bothered first. They’d much rather spend their time swimming at depths of about 60 to 100 feet, coasting around obstacles and looking for their next meal of small fish, crustaceans or squid. “You’ll find them around a lot of shipwrecks on the Carolina coast,” says aquarist Ray Popik. “They hang out around the top of the wreck … they don’t like to get down low and navigate between things.”

The sandtiger’s docility, though, develops only after it’s born. The pre-birth behavior of the species is just about the most brutal example of natural selection in the entire ocean. Along with several other shark species, the sandtiger has been known to practice intrauterine cannibalism — during pregnancy, the first pup to hatch uses the other eggs and embryos in the mother’s uterus as a food source. “The first egg that hatches wins,” says Popik. “It’s a pretty gnarly process, but in the end it allows them to provide the most amount of nutrition to put out the largest, most well-developed shark possible as a newborn.”

The sandtiger shark is also the only shark species that exhibits a certain hunting behavior: They are known to swim to the surface and gulp air into their stomachs, giving their bodies more buoyancy. This enables them to hover in the water with ease and stalk their prey by remaining completely motionless until the right time to strike. So, while they may not be the most aggressive swimmers or the most ravenous eaters, but when the time comes to feed they can put all those teeth to good use.

It doesn’t take long to find a sandtiger shark on a typical visit to the Aquarium. Their awe-inspiring stature and protruding rows of teeth catch the eyes of guests almost immediately as they enter the shark gallery. Popik agrees that their appearance combined with their behavior gives them an air of quiet dignity. “They have a presence in the exhibit,” he says. “The way they just cruise around; you can tell nothing bothers them.” Indeed, simply watching a sandtiger glide by or even overhead in the sea tube inspires a sense of respect for ocean life few other creatures can match.

Shark Spotlight: Sandbar Sharks

It’s that time of year again—Fin Fest! Sharks are already on our minds 24/7, but this week-long celebration of sharks (July 22 – 29, 2018) gives us an excuse to really show how much we appreciate these jaw-some animals.

Also known as the “brown shark” due to their muddy-gray appearance, the sandbar shark is most commonly found in shallow coastal waters with a population distribution that touches every continent except Antarctica. Despite being prevalent on an international scale, some of the largest groups of sandbars can be found relatively close to Northeast Ohio. In fact, they’re the most common species of shark in the western Atlantic Ocean. Large nursery grounds in the Chesapeake Bay, Delaware Bay and in parts of the Carolina coast make them a very common shark species around popular beach vacation spots for Clevelanders. Their population in these areas takes a huge hit in the winter, however, as their migration patterns take them as far south as the Gulf of Mexico in search of warmer water.

At the Aquarium, sandbar sharks are a perennial favorite due to their more active, agile swimming habits. Their tendency to traverse a lot of vertical space in the exhibit and make sharp, sudden turns shows off their distinctive body shape and makes them exciting to watch. Their shape in particular is what aquarist Ray Popik describes as a “classic shark look.” Their uncommonly tall dorsal fins, short snouts and wide pectoral fins give them a sleek profile that draws a lot of attention. “Sandbars are very stereotypical and jet fighter-looking,” says Popik. “They’ve got that nice, tall dorsal fin which gives them the look you picture when you think about a shark.”

Showing off their athletic swimming ability and undeniably cool appearance, sandbar sharks don’t just bridge the gap between the nurse and sandtiger — they’re proof that even the most common shark species are something truly extraordinary.

Shark Spotlight: Nurse Sharks

It’s that time of year again! Fin Fest is only a few weeks away, and we can’t wait to welcome shark lovers of all ages to the Aquarium to celebrate with us. Sharks are already on our minds 24/7, but Fin Fest gives us an excuse to really show how much we appreciate these jaw-some animals.

This week we’re covering the nurse shark, the sedentary bottom-dweller that can be found hanging around the lower, more secluded areas of the shark gallery. There are a few theories on how nurse sharks got their unusual common name. Most agree that it comes from the old English word “hurse,” meaning “seafloor shark,” but others argue the name was inspired by the sound they make while hunting which is often compared to a nursing baby.

The unique noise comes from their feeding technique, which involves sucking their prey up from the seafloor like a vacuum. Their mouths are just big enough to eat things that live near the bottom, like snails, crustaceans and mollusks, but too small to hunt for larger fish like their fellow sharks do. Being nocturnal hunters, they’ll begin to prowl the seafloor for food at night using the the whisker-like barbels that extend from their face to feel around for things to eat. “Here in Ohio, we think ‘Oh, that looks like a catfish,’” says aquarist Ray Popik of the nurse shark’s appearance, “and they actually do fill a bit of the same ecological niche.”

According to Popik, all of these characteristics go hand-in-hand. “During the daytime you’ll see them underneath ledges and in crevices hiding out. Then at night they’ll cruise the bottom scavenging for food,” he says. “Typically the more bottom-oriented the shark is, the more nocturnal it is. The opposite is true for sharks that are more active hunters, and nurse sharks are usually scavengers in the wild.”

Contrary to the popular belief that all sharks have to remain constantly swimming in order to breathe, nurse sharks and their seafloor-inhabiting peers can push water over their gills themselves without having to move much. They can circulate water through their systems by opening and closing their mouths, which allows them to stay put. The nurse shark’s bottom-dwelling habits usually catch the eye of Aquarium guests, as their behavior differs from the constant cruising of their “gallery mates” the sandtiger and sandbar sharks. However, Popik says their behavior is relatively common for seafloor shark species. “[Their behavior] is unique out of our three species,” he explains, “but it’s not terribly unique in the wild.”

Hanging out in the lower regions of their exhibit, the calm-and-collected nurse shark shows us how varied shark behavior can be in nature. Next week we’ll be talking about the sandbar shark, whose agile swimming and striking silhouette make it one of the most fun to watch animals here at the Aquarium — and don’t forget, Fin Fest is happening right here every day from July 22nd through the 29th. If you love sharks as much as we do, it’s the place to be, so don’t miss out.

Father’s Day Heroes: Seahorses vs. Seadragons

We’re gearing up for Father’s Day, which made me think about the many different kinds of “wild” dads there are here at the Aquarium. While they’re all deserving of our appreciation, none go above and beyond quite like seahorses and weedy seadragons. When these species reproduce, it’s the male who nurtures the developing embryos and carries them to term. In short, pregnant dads! Really makes you rethink gender roles, doesn’t it?

This unique reproductive method is exclusive to the family Syngnathidae, which also includes pipefish and pipehorses. Some other things all syngnathids have in common are fused jaws, the absence of pelvic fins and thick, bony armor covering their bodies — but male pregnancy, in terms of pure “wow” factor, is their main calling card as a group of species. The female deposits the unfertilized eggs with the male, who then cares for the growing embryos until they’re born. However, no two syngnathids share the exact same reproductive process. This includes our seahorses and seadragons, who differ in a couple of interesting ways.

First of all, the seadragon and the seahorse carry fertilized eggs in different locations. A pregnant seahorse looks pretty familiar to us humans, as they carry their young (who often number in the thousands, by the way) in a pouch located in their abdominal area. This gives them a sort of potbelly appearance. Seadragons, on the other hand, carry their eggs on a specialized patch of skin at the base of their tails.

The hatching processes of the two species are also completely different. Seahorses’ brood pouches begin to expand right before they give birth. This happens as the fully-grown seahorse embryos begin to hatch from their egg membranes and move freely around the pouch. Once the pouch is at capacity, the seahorse finally gives birth, releasing the entire brood at once in dramatic fashion.

Meanwhile, seadragons give birth to their brood more slowly over a period of several days. The baby seadragons hatch one by one rather than all at the same time, decreasing the competition for food by dispersing the brood over a larger area of ocean. You could say seadragon dads go the extra mile to set their kids up for survival in the wild, however, it doesn’t look as impressive in captivity.

If you want to see these amazing aquatic parents up close, come visit us at the Greater Cleveland Aquarium in the First Energy Powerhouse on the West Bank of the Flats. Bring your own dry-land dad on Father’s Day, June 17^th, and he’ll get in free with the price of a general admission ticket — find out more here.

 

 

 

 

How a President Propagated a Piranha Myth

Blockbuster thrillers like Jaws have given sharks an undeserved reputation as aggressive, man-eating killers. Similarly, stories about piranhas have portrayed this fairly calm species as bloodthirsty animals to be feared.

So where did this myth begin?

In 1913, Theodore Roosevelt made a trip to Brazil. To impress the adventurous former American President, locals took him deep into rainforest and allowed him to “discover” a river there but warned him not to venture in. What he did not know was that they had stocked the waters with unfed piranhas. To illustrate the dangers for the former President and accompanying journalists they threw a cow into water filled with starving piranhas. (Was it a dead cow? Bloody bits of diced meat? A sick cow? This detail seems to change from story to story.)  Within moments there was a massive feeding frenzy.

Roosevelt went on to record his amazement of these seemingly perfect killing machines in his travel memoirs, which the American population devoured and became weary of the species. In 1914’s “Through the Brazilian Wilderness”, Roosevelt noted the following:

“They are the most ferocious fish in the world. Even the most formidable fish, the sharks or the barracudas, usually attack things smaller than themselves. But the piranhas habitually attack things much larger than themselves . . . the piranha is a short, deep-bodied fish, with a blunt face and a heavily undershot or projecting lower jaw which gapes widely. The razor-edged teeth are wedge-shaped like a shark’s, and the jaw muscles possess great power. The rabid, furious snaps drive the teeth through flesh and bone. The head with its short muzzle, staring malignant eyes, and gaping, cruelly armed jaws, is the embodiment of evil ferocity; and the actions of the fish exactly match its looks.”

Although not based on real-world circumstances, Roosevelt’s vivid account the experience has only gained momentum over the years. Once Hollywood latched onto the myth and created the 1987 film “Piranha,” the unfortunate characteristic stuck.

In truth, piranhas are relatively calm until spooked. This animal can be skittish, especially if there are a larger number of them in one exhibit. The Red-Bellied Piranha, native to South America, feed on fish, snails, insects and aquatic plants, only occasionally eating larger mammals and birds.

We caught up with Connor while he was feeding our red-bellied piranha and asked him for the real story behind these beautiful fish.

Curious to learn more? Check out:

• Hidden History – The Myth of the Piranha
• OPEFE Archives – Legendary Myth of Piranha Revealed, as reported by H. R. Axelrod
• Our Blog – Hollywood Hoax: Busting The Myth Of The Piranha
• Zoologger – Sympathy for the Piranha

– Morgan Wright