Remarkable Rays and Super Skates

The information contained in this website is believed to be correct, but we are always striving to learn the truth and the facts about these often misunderstood animals, Across the world more is being discovered day by day, so if you see something on the site and you have a question about it, please get in touch with us. 

Facts and Figures

Rays vastly vary in size. The smallest ray is the short-nose electric ray which is approximately 10cm across and weighs about 400g (the size of a pancake). The manta ray is the largest ray reaching up to 7m in wing span and weighs 2,000kg.

By SEFSC Pascagoula Laboratory; Collection of Brandi Noble, NOAA/NMFS/SEFSC. - NOAA Photo Library: fish4345 (SEFSC Pascagoula Laboratory; Collection of Brandi Noble, NOAA/NMFS/SEFSC http://www.photolib.noaa.gov/htmls/fish4345.htm), Public Domain, https://commons.wikimedia.org/w/index.php?curid=17940959

Rays are almost as old as dinosaurs. Fossil records date rays back to the Jurassic period, 150 million years ago!

By Giuseppe Marramá, Ortwin Schultz & Jürgen Kriwet - G. Marramá, O. Schultz & J. Kriwet: A new Miocene skate from the Central Paratethys (Upper Austria): the first unambiguous skeletal record for the Rajiformes (Chondrichthyes: Batomorphii). In: Journal of Systematic Palaeontology, 2018, 24 S., CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=77508048

Scientist say that a manta ray can swim at speeds of up to 43 miles per hour, or 70 kilometers an hour. Now that is fast!

Like sharks, rays are known to breach clear of the water. They don’t do this to catch prey, they do this to escape their predators, clear themselves of parasites or to look good and attract a mate.

By Nick Bonzey from Corvallis, OR - Bat Rays catching some air, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=5442007

Click here to head to the BBC Earth site to watch some stunning video of mobula rays breaching.

The general body shape of sting rays, rays and skates can vary greatly:

Circular sting rays prefer to inhabit the bottom and undulate their ‘wings’ to move.

Skates are more diamond shape and also inhabit the bottom.

By User: (WT-shared) Pbsouthwood at wts wikivoyage, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=22711066

Then eagle rays who inhabit open ocean and ‘fly’ through the water. 

Electric rays are known for being capable of producing an electric discharge, ranging from 8 to 220 volts. This is used both to defend them from predators, and to catch prey. To give some perspective 220 volts is enough to run a hair drier.

By Kora27 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=67526203

Like sharks, skates and rays don’t have a swim bladder, but use their oily liver for buoyancy. When they stop swimmming they sink down to the sea bed.

Rays and skates are flattened fish closely related to sharks. All belong to a group of fish called Elasmobranchs. None of them have any bones in their body – their skeleton is made up of flexible cartilage (the bendy stuff that your ears and nose are made from!)

Testing your Senses

Rays and skates have a high ratio of brain weight to body weight so they are probably very intelligent – possibly even smarter than sharks! The are very curious animals, often approaching divers and observing what is happening round them.

Sting rays and skates are very well adapted to a bottom dwelling life. They can bury themselves in the sand and use their spiracles to breath. From above you will see their spiracles and eyes, but not their mouths – a feature they share with bottom dwelling sharks.

Rays use a super set of senses to search for food. Special gel-filled pits (also called pores) across the front of their face, (called Ampullae of Lorenzini), allow them to pick up electrical signals from other animals when they move – cool! This is called electroreception. Their eyes are on the topside of their body and their mouth and gills can be found underneath, so in the darker depths or murky rivers this electromagnetic sense is especially useful for searching for prey.

 While sharks also have electrosensory pores, there are more pores found on rays/skates due to the larger surface area that is in contact with the ground when hunting for prey.

Sharks and rays/skates have many different types of teeth, which match the very diets they have. Sharks have biting teeth like our front incisors which we use for biting and some have crushing teeth for eating molluscs and crabs. Rays and Skates have generally flatter teeth, more like our back molar teeth, that are use to crush their smaller prey.

Bet you didn't know this...

Many rays like to live by themselves and only come together for  breeding and migration. Some of the largest rays such as manta rays and cownose rays never stop swimming and migrate in their thousands to feeding grounds each year. These large groups can reach up to 10,000 individuals and are known as a “fever“.

By Leonard Clifford from Sydney, Australia - Pigmy Manta Rays, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=30922933

Skates and Rays mate on the go.  The female gives off scents to tell the males that she is ready to mate. Sometimes she can mate with 3 or 4 males before being fertilized. 

Click HERE to head to Youtube and see a video of eagle ray mating

Interestingly, the largest ray is a filter feeder, just like the largest of all the sharks the Whale shark and the second largest the Basking shark. Feeding on tiny plankton rather than competing for larger mammals and fish prey is an interesting strategy that all three have evolved to acquire.

By Arturo de Frias Marques - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=35740544

A Sting in the Tail …

Not all rays have barbs on their tails, only true sting rays. They can have between 1 and 7 barbs on their tails which are made from calcified cartilage and some are venomous. The edges are serrated like a knife so that the barb goes into a prey/victim easily but it does more damage as it comes out. If the barbs break off from the tail they can regrow, but this is a slow process. This is why they would rather swim away than sting something.

In comparison to rays, skates have thorny projections, which are basically made up of a thorn inside of a little calcium deposit in the skin. If the skate gets attacked, the thorn can come out without causing injury to the animal itself.

Stingray venom is similar to a jellyfish sting, if a person is stung the immune system will influence whether they will react to it or not.

RAYS

Venomous spines or barbs in their tail. 

SKATES

Thorny projections on their back & tails.

barbs

Rays are ovoviviparous, meaning the young are hatched from eggs that are held within the body.

Skates are oviparous, meaning they lay eggs – these eggs are protected by a hard, rectangular case often called a “mermaid”s purse“.

Misunderstood

Popular Australian naturalist, Steve Irwin, died in 2006, aged 44, while filming at the Great Barrier Reef for a conservation TV series. While snorkelling chest deep in shallow waters he was stung by a stingray it is believed, due to a defensive response and died after excessive bleeding when its barb pierced his heart. It is not entirely clear why the ray reacted in this way as he had spent time with the same animal earlier in the day without any incident.

Steve’s tragic, but unusual, death resulted in a significant increase in people’s fear of stingrays.

However stingrays do not actively seek out humans to attack. They are very docile animals that only attack when they feel threatened. The most common threat is a person stepping on one by accident. Stingrays also feel threatened if a person swims directly over or in front of them, blocking their escape route.

If stung, most stingray venom isn’t lethal to humans. Although extremely painful, stingray venom is rarely deadly. In fact, in ancient Greece venom was extracted from stingray spines and used as an anesthetic.

If skates and rays could speak

they would be asking for help

Sadly, skate and ray numbers are in decline. Overfishing, habitat loss and climate change are their major threats. Some of the filter feeding species, such as Manta rays are also hunted for their gill rakers (used for feeding) for use in Chinese medicine. At present, 539 species of ray and skate species have been assessed are under the IUCN Red List, and 107 are classified as threatened.

Time to get involved and offer your help?

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