Short-tail stingray facts for kids
Quick facts for kids Short-tail stingray |
|
|---|---|
 |
|
 |
|
| Conservation status | |
Scientific classification  |
|
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Myliobatiformes |
| Family: | Dasyatidae |
| Subfamily: | Dasyatinae |
| Genus: | Bathytoshia |
| Species: |
B. brevicaudata
|
| Binomial name | |
| Bathytoshia brevicaudata (F. W. Hutton, 1875)
|
|
 |
|
| Range of the short-tail stingray | |
| Script error: The function "autoWithCaption" does not exist. | |
| Synonyms | |
|
|
Script error: No such module "Check for conflicting parameters".
The short-tail stingray or smooth stingray (Bathytoshia brevicaudata) is a large and common type of stingray. It belongs to the Dasyatidae family. You can find this amazing creature off the coasts of southern Africa, southern Australia, and New Zealand. It lives in waters from very shallow areas near the shore down to about 480 meters (1,575 feet) deep.
This stingray mostly lives on the ocean floor, but it also swims into open water sometimes. It can be found in many different places, like estuaries (where rivers meet the sea) and rocky reefs. The short-tail stingray is one of the biggest stingrays in the world! It can grow to be over 2.1 meters (7 feet) wide and weigh up to 350 kilograms (770 pounds).
Its body is shaped like a diamond and is usually plain dark grey or black. Sometimes it has rows of white spots. Unlike many other rays, its skin is smooth, even when it's an adult. It has white pores near its head. Its tail is usually shorter than its body and is thick at the base. The tail has large bumps and a row of big, sharp spines before its main stinging spine. Behind the sting, there are folds of skin that look like small fins.
Short-tail stingrays eat invertebrates (like crabs and clams) and bony fishes. They tend to stay in the same general area all year. During winter, they prefer deeper waters. Large groups of these rays gather in certain spots, especially in summer, like near the Poor Knight Islands in New Zealand. This is where they find partners and give birth. Female stingrays give birth to live young, usually 6 to 10 pups at a time. The babies grow inside their mother, getting special milk-like fluid for nourishment.
Even though they are not usually aggressive, their long, venomous sting can cause a very serious injury. Fishing boats sometimes catch them by accident, but most survive and are released. Scientists believe their population is healthy, so the International Union for Conservation of Nature (IUCN) lists them as "least concern," meaning they are not currently threatened.
Contents
Discovering the Short-tail Stingray
A scientist named Frederick Hutton first described the short-tail stingray in 1875. He was the curator of the Otago Museum in New Zealand. He studied a female ray that was about 1.2 meters (4 feet) wide, caught near Dunedin. Hutton published his findings in a science magazine called Annals and Magazine of Natural History.
He named the new species Trygon brevicaudata. The name comes from Latin words: brevis means "short," and cauda means "tail." For a long time, this ray was known as Dasyatis brevicaudata. However, after more recent studies in 2016, scientists decided it belongs to a different group called Bathytoshia. This is why its scientific name is now Bathytoshia brevicaudata.
People also call this ray by other names, such as the giant black ray, giant stingray, or smooth short-tailed stingray. It is closely related to the pitted stingray (Dasyatis matsubarai), which lives in the northwestern Pacific Ocean. DNA studies in 2016 suggested that some other stingray populations might actually be the same species as the short-tail stingray.
What Does the Short-tail Stingray Look Like?
The short-tail stingray has a strong, heavy body that is usually very smooth. Its main body, called the pectoral fin disc, is shaped like a diamond and is a little wider than it is long. The front edges of its body curve gently to a blunt, triangle-shaped nose.
Its eyes are small, and right behind them are much larger breathing holes called spiracles. Its nostrils are long and narrow, with a short, skirt-shaped flap of skin between them that has a frilly edge. The mouth is a moderate size with a curved lower jaw. It has small, nipple-like bumps on the floor of its mouth.
Short-tail stingrays have between 45 and 55 small, blunt, cone-shaped teeth. These teeth are arranged in a grid-like pattern. The pelvic fins, located near the tail, are somewhat large and have rounded tips.
The tail is usually shorter than the body disc. It has one, and sometimes two, jagged stinging spines on its upper side, about halfway along its length. The tail is wide and flat until the sting, then it quickly gets thinner. It has a noticeable fold of skin underneath and a low ridge on top.
Only the tail has dermal denticles, which are tiny, tooth-like scales. Adult rays have a row of large, backward-pointing, spear-like bumps or flattened thorns down the middle of their tail, in front of the sting. They also have much smaller, cone-shaped thorns behind the sting, covering the rest of the tail.
The top of the ray's body is grayish-brown, getting darker near the tail tip and above the eyes. It has a line of white pores on each side of its head. The underside is whitish, becoming darker near the edges of its fins and under its tail. Some rare individuals have been seen that are completely white, known as albinos.
This is the largest stingray species! It can grow to be at least 2.1 meters (7 feet) wide, 4.3 meters (14 feet) long, and weigh up to 350 kilograms (770 pounds). People in New Zealand have even reported seeing some that are almost 3 meters (10 feet) wide. Adult females are about one-third larger than adult males.
Where Do Short-tail Stingrays Live?
The short-tail stingray is common and lives in the cooler waters of the Southern Hemisphere. You can find it off southern Africa, from Cape Town to Mozambique. Along the southern coast of Australia, it lives from Shark Bay to Queensland, including Tasmania. In New Zealand, it is found around North Island and the Chatham Islands. It is rarely seen near South Island and the Kermadec Islands.
Reports of this ray in northern Australia and Thailand are likely other species that look similar. Over the last few decades, more short-tail stingrays have been seen off southeastern Tasmania. This might be because of climate change.
Off southern Africa, these rays are not often found in shallow water. They usually live over underwater hills called banks, at depths of 180 to 480 meters (590 to 1,575 feet). However, off Australia and New Zealand, they live in very shallow coastal areas down to about 156 meters (512 feet). Australian and New Zealand rays are most common in shallow waters during the summer.
A study tracking two rays in New Zealand showed that they moved to deeper waters in winter. However, they did not travel very long distances. The short-tail stingray mostly lives on the ocean floor. It can be found in many different places, including brackish estuaries (where fresh and salty water mix), sheltered bays, sandy flats, rocky reefs, and the edge of the land under the sea (the continental shelf). But it also often swims up into the open water above the bottom.
How Short-tail Stingrays Live and Eat
The short-tail stingray usually moves slowly. But it can suddenly swim very fast! When it flaps its fins quickly, it can push the water so hard that it creates bubbles and a loud "bang." This is called cavitation.
These rays gather in large groups at certain times of the year. A famous gathering happens every summer (from January to April) at the Poor Knight Islands off New Zealand. They especially like to gather under rocky archways there. In some places, they swim into very shallow water when the tide comes in.
Each ray tends to stay within a fairly small area, usually less than 25 kilometers (15 miles) from its home. Scientists have learned that these rays can detect magnetic fields using special sensors. This might help them navigate in the ocean.
The short-tail stingray looks for food both during the day and at night. It mainly eats fish and creatures that live on or near the bottom, like molluscs (such as clams) and crustaceans (like crabs). It has a special sensory system called the lateral line on its underside. This helps it find tiny water jets made by buried clams and spoon worms. It then sucks them out of the sand. It also eats fish and small creatures that swim in open water, like jelly-like salps and tiny shrimp-like animals.
Off South Africa, these rays have been seen hunting near the egg beds of chokka squid when many squid come to lay their eggs. The short-tail stingray has few predators because of its large size. However, large sharks like the copper shark, smooth hammerhead, and great white shark, as well as killer whales, sometimes hunt them. When a ray feels threatened, it raises its tail like a scorpion as a warning. Smaller fish have been seen using swimming rays for cover while hunting their own prey. This species can have tiny parasites living on or in them.
Life Cycle and Reproduction
The summer gatherings of short-tail stingrays at the Poor Knight Islands are important for reproduction. Both finding partners and giving birth have been seen among the rays there. They find partners in the open water. The strong currents in the archways might help the rays stay in place during this time.
Males will try to get the female's attention. When a female is ready, a male will join her to fertilize her eggs. This process can last a few minutes. Females in captivity have been seen with multiple partners.
Like other stingrays, the short-tail stingray gives birth to live young. The baby rays grow inside their mother. First, they use a yolk sac for food. Then, they get a special milk-like fluid from their mother's body, which is rich in nutrients.
Females usually give birth to 6 to 10 pups in the summer. Males sometimes gently nudge the female's belly during birth. Females can have more babies soon after. Newborn rays measure about 32 to 36 centimeters (13 to 14 inches) across.
Short-tail Stingrays and Humans
Short-tail stingrays are often curious and not aggressive. They may approach humans and can even be trained to be hand-fed. At Hamelin Bay in Western Australia, many short-tail stingrays and other rays regularly gather to be hand-fed fish scraps. More and more visitors come to see them, and there is interest in making it a permanent tourist spot.
However, if a ray is startled or bothered, its sting can cause a very serious injury. The sting can be over 30 centimeters (12 inches) long and can go through most types of shoes. Its protective covering contains a poison that can damage tissue. The most dangerous injuries can affect important body parts, cause a lot of bleeding, or lead to serious infections. A startled ray can also leap through the water and cause injuries with its tail. This species is responsible for most stingray injuries in New Zealand. A sad incident involved Australian naturalist Steve Irwin, who was fatally stung when a stingray pierced his chest.
Fishing boats sometimes accidentally catch short-tail stingrays using different types of nets and lines. Some people catch them for sport or food. A few are also kept for display in public aquariums, where they have reproduced. Since this species survives fishing activities well and remains common, the International Union for Conservation of Nature (IUCN) has listed it as "least concern." This means it is not currently threatened. In most of New Zealand, it is against the law to fish for them commercially. In June 2018, the New Zealand Department of Conservation classified the short-tail stingray as "Not Threatened" with the note "Secure Overseas."
Images for kids
-
A short-tail stingray swimming
-
Another view of the short-tail stingray
See also
In Spanish: Bathytoshia brevicaudata para niños
