One of the most unusual creatures found in the world’s waters, rays make for some highly fascinating marine life. Dating back 150 million years to the Jurassic Period, they’ve certainly learned a thing or two in that time – evolving and developing into the unique animals they are today. Looking to learn more about the different ray species? With the help of one of our expert trainers, we’ll tell you more about this intriguing species, as well as what to expect from the rays we keep at Bristol Aquarium!
What are rays?
Rays are a type of cartilaginous fish, making them related to sharks. This means they have a skeleton made from cartilage, as opposed to bone. They are part of the order Batoidea and are the largest group of cartilaginous fish.
Together with sharks, skates and sawfish, they make up the subclass Elasmobranchii, characterised by cylindrical or flattened bodies.
How many species of rays are there?
There may be as many as 600 different species of rays and skates around the world, categorised into different families such as Dasyatidae (stingrays), Myliobatidae (eagle rays), Mobulidae (manta rays) and Rajidae (skates).
Rays and skates are essentially the same type of animal, with the main difference being that rays have whip-like tails while skates have stockier tails. Another difference is that skates will lay eggs while rays give birth to live young.
What do rays and skates look like?
Rays typically have wide, flat bodies. Some have kite or diamond-shaped bodies, while others are more rounded. They have eyes with a mouth and gills on the underside of their body, and pectoral fins which just look like an extended part of their flat bodies.
Both rays and skates have a spiracle, which is a respiratory opening that sits behind their eyes. The spiracle allows the ray or skate to breathe when partially buried in the sand. They also both have a tail, which is actually the caudal fin.
Do all species of rays have a barbed tail?
There are so many different types of rays, and only some of them have what’s known as a barbed tail. A barbed tail means that it has spines or stings, which the ray can use as a defensive mechanism to protect itself from predators. The barb is a pointed part of the tail that acts as a fishhook or arrowhead.
Stingrays have barbed tails, hence their name! The barb is venomous, as well as having serrated edges. Eagle rays are also known to have barbs, while manta rays don’t. Instead, manta rays will rely on their speed to evade any predators they may have – which aren’t many.
Skates do have thorny tails, with extra spikes running along their back, but they aren’t venomous.
Wild rays’ typical habitat
Rays can typically be found in both saltwater and freshwater, as well as shallow and deep areas, depending on their species. However, they are mostly marine animals, with many being found at the bottom of the seabed.
Stingrays for example are usually found in the shallower coastal waters of temperate oceans, but spend a lot of time partially buried in the sand. Skates are also found across the world, but can be found in both cold and temperate climates.
Can you find rays in the UK?
There are around 18 species of rays that can be found right here off the coast of the UK! This includes common stingrays (Dasyatis pastinaca) and thornback rays (Rajidae). You can even find evidence of them along the beach in the UK. Ray egg cases – also known as mermaid’s purses – can be found washed up on beaches around the country. You can actually join the egg case hunt, carried out by the Shark Trust, to help them identify and record shark and ray eggs washed up on our coastline.
What do rays eat?
Rays aren’t the fussiest of eaters, and will eat a variety of things! Their diet typically consists of molluscs, fish, squid and crustaceans. Similarly, skates will feed on bottom dwelling creatures like shrimp, oysters, crabs and other invertebrates.
Fully grown rays don’t have many predators, but the ones they do can be sizeable – including sharks, seals and sea lions.
How do rays move through water?
Most rays swim by either oscillating or undulating their bodies, which means they move a bit like a wave does. Others flap their sides like wings to move through water. Their tails can also be used to help them manoeuvre through water.
They are amongst the smoothest swimmers in the sea, seeming to simply glide or fly through the water with little effort. They are known to swim around 10mph, but some manta rays are capable of swimming in bursts of around 22mph which can be helpful when evading danger.
Lifespan and reproduction
One of the biggest differences between skates and rays is their reproduction style. Rays give birth to live young, but this can happen in two ways. In some species, the females will keep the eggs until they have hatched inside the uterus, until they are ready to be born once the egg yolk has been used up. The second way is where the egg yolk develops into the placenta attached to the wall of the uterus and they are then born alive, like in mammals.
The eggs contain the sac that provides the necessary food fo the offspring, and they can take anywhere from 5-12 months to fully develop.
Skates on the other hand give birth to eggs, which is known as oviparity. Their eggs are laid in a protective case that is known as a mermaid’s purse. In both skates and rays, the young are left to fend for themselves from birth.
Rays and skates’ lifespans can depend on the species, but typically they will live for 15-25 years. Manta rays however have been known to live for around 50 years!
How do we look after our rays at Bristol Aquarium?
Here at Bristol Aquarium we have rays in two different exhibits, with saltwater rays found in our Bay of Rays exhibit and freshwater rays in our Amazon area.
Our rays are trained to come over to a station to be fed by the keepers. We throw in food for the mullet and other fish in our bay of rays tank, which gets the rays excited, and they swim over to the front of the tank by the glass. We can then use grabbers to feed each ray individually – this helps us to know who is feeding, how much they are eating, and gives us a good opportunity to check their overall health.
The hardest part is definitely telling them apart, as many of them look the same and there are a few of each species in the tank. We have to use unique markings on their bodies to help work out who is who.
Come and see our fascinating rays and skates and book your tickets today!