We are going Batoid for Spotted Eagle Rays in this Ultimate Guide to Aetobatus narinari!
Related to the manta ray and other marine batoids (rays), these stunning animals can be identified by their unique spotted patterns on their backs, and found soaring majestically through tropical waters.
Table of contents
- Where do Spotted Eagle Rays live?
- How did Spotted Eagle Rays get their name?
- Spotted Eagle Ray Size
- How do Spotted Eagle Rays Breathe?
- Why are Spotted Eagle Rays dark on top but white on the bottom?
- What do Spotted Eagle Rays eat and how?
- Spotted Eagle Ray Predators
- Are Spotted Eagle Rays dangerous?
- Do Spotted Eagle Rays migrate?
- Why do they jump out of the water?
- Spotted Eagle Ray Superpowers
- Are Spotted Eagle Rays Endangered?
- Get FACTED!
Where do Spotted Eagle Rays live?
Spotted eagle rays can be found around the world in tropical waters. The Atlantic population is considered to be the true spotted eagle ray, Aetobatus narinari. In the Atlantic, these animals can be found in the Caribbean from the southeast coast of the USA to Brazil, and along the African coast from Cabo Verde to Namibia. There are similar rays in the Indo-Pacific (the ocellated eagle ray) and the Eastern Pacific (the Pacific white-spotted eagle ray), but they are different species from the Atlantic population.
How did Spotted Eagle Rays get their name?
The spotted eagle ray, Aetobatus narinari was first described in the late 1700s by a botanist on a trip to the Antilles. Very cleverly, “Aeto” means “eagle” and “batus” means ray. Instead of staying close to the sea floor, these animals like to swim across pelagic waters (open ocean). Soaring through the water makes these rays look like eagles flying, and so they became the eagle rays.
Spotted Eagle Ray Size
Only manta rays beat them in size; these majestic creatures can have wingspans up to 11 feet (3m)! Spotted eagle rays are very active, and they need these huge fins to propel them across oceans and from the depths to the surface as they hunt. Spotted eagle rays with can be 16 ft (5m) long and reach a weight of over 500 lbs (230 kg).
How do Spotted Eagle Rays Breathe?
Spotted eagle rays have five gills on each side of their body. Spotted eagle rays need to keep swimming to breathe, so they can continue to absorb oxygen from the water passing through their gills.
Why are Spotted Eagle Rays dark on top but white on the bottom?
Spotted eagle rays are big and have an incredible sense of smell, which means that they thrive in the open ocean.
If you look down in the open ocean, you see darkness below. If you look up in the open ocean, you see the bright surface. Spotted eagle rays have “countershading” camouflage – dark on top and light on the bottom – to be hidden from predator view both above and below. The spots give them extra camouflage as they swim over reefs during migrations or to hunt for prey.
What do Spotted Eagle Rays eat and how?
Spotted eagle rays have what some call a “duckbill” snout. This long, broad snout is used to dig into the sand until there’s a huge cloud of sand all around and the ray finds a snack. Spotted eagle rays can turn over rocks and poke into reef crevices.
Spotted eagle rays like to eat small creatures that they dig out of the seafloor with their snouts. Their favorites include crustaceans (crabs, shrimp), bivalves (clams, oysters), gastropods (sea snails) and small octopus and fish.
How do they break through those shells? Spotted eagle rays have specialized teeth to help them crush through hard shells. Their teeth are actually two hard plates with a grooved chevron pattern, allowing them to crunch through the hard shell of any prey that catches their eye.
Once they find something tasty, they suck it into their mouth and crush it with their flat teeth that are like jagged plates, specifically designed to crush shells. Spotted eagle rays also have papillae, small projections used to remove shells from the prey. They spit the shells, eat the soft parts, and move along to the next morsel.
Spotted Eagle Ray Predators
Sharks are the about the only thing big and fast enough to eat spotted eagle rays. Species like the tiger, lemon, silvertip, bull, and hammerhead sharks have been seen preying on spotted eagle rays. The sharks sometimes follow pregnant females and wait to eat her newly born pups, but preying on adults takes much more effort. Sharks will bite a pectoral fin first, to make sure the eagle ray can’t swim away quickly. Then the shark will pin the ray against the seafloor and eat it, headfirst. But this is not always how it goes; spotted eagle rays can be fierce competitors.
Spotted eagle rays have camouflage to prevent them from being seen. They use their soft bodies, made of cartilage (not bone) to make sharp turns in a chase. If a predator gets too close, spotted eagle rays can leap out of the water to evade and confuse predators before swimming away safely. And as a last resort, spotted eagle rays have a venomous weapon: tail spines. Anywhere from two to six small, barbed spines filled with venom await any predator that gets too close.
Because of these defenses, it’s very rare to witness a spotted eagle ray being eaten.
Are Spotted Eagle Rays dangerous?
There have been injuries when spotted eagle rays accidentally leapt onto boats and landed on boaters, but spotted eagle rays are timid creatures who tend to avoid human interaction. Like many animals, spotted eagle rays have defenses to use if they are provoked.
If a predator approaches a spotted eagle ray, it may find itself on the wrong edge of a venomous tail spine.
Even if a spotted eagle ray finds a human interesting underwater, it will still keep its distance. You may be lucky enough to watch it fly by, so have your camera ready!
Do Spotted Eagle Rays migrate?
Yes, but there is a lot we don’t know about spotted eagle ray migration. Eagle rays can be found traversing the ocean alone or in schools. These animals migrate long distances during the same seasons each year, which makes scientists think they migrate to stay within optimal conditions to find prey. Though spotted eagle rays migrate throughout the year, they come back home.
Why do they jump out of the water?
There are many theories, but no proven answers yet. Spotted eagle rays may be jumping:
- to avoid predators chasing them
- to shake off parasites and remoras (animals that live on them)
- to avoid unwanted male attention
- just for fun!
Spotted eagle rays may be jumping out of the water for any or all of these reasons, but what do know is that it’s incredible to watch.
Spotted Eagle Ray Superpowers
Spotted eagle rays have electroreception: they can sense electric energy.
Marine animals produce electrical signals, and spotted eagle rays can detect those signals to find prey. In their snout, there is a cluster of jelly-filled pores that are extremely sensitive to electrical signals, which allows them to sense prey if it’s swimming by, crawling below, or even buried in the sand.
Are Spotted Eagle Rays Endangered?
Spotted eagle rays are listed by the IUCN as “Near Threatened”. Populations are in decline because spotted eagle rays can only give birth to 2-4 pups a year, and there are many threats to the species.
These animals are hunted by a variety of sharks. Spotted eagle rays are caught globally to be moved into aquariums, and in some places (primarily Southeast Asia and Africa) they are fished to be used for fishmeal and oil. And while they are not targeted by fisheries in every country, they often end up as bycatch: accidentally caught in fishing gear that was trying to target another species.
Eagle rays help support marine ecosystems and are a big tourist attraction, so people around the world want to protect this species. To know how to protect something, you have to understand it first. Plenty of information on spotted eagle rays remains a mystery. Why do they leap out of the water? Where do they migrate? Who do they migrate with? Which populations are connected? Luckily, there are groups of people trying to answer these questions.
How you can help the spotted eagle rays
The Eagle Ray Project – Mexican Caribbean is one of those groups.
Spotted eagle rays have unique spot patterns on their back, like our fingerprints. If there was a way to pinpoint the location of an eagle ray and what individual it was, you could track that individual. Welcome to the world of photo identification.
The Eagle Ray Project uses citizen scientists: people in the general public willing to submit their eagle ray photos to a huge database. These photos are submitted with information: where the photo was taken, when, and if the eagle ray was alone. Photos are run through software to be identified by their unique spot patterns, and each unique eagle ray is given a name. After collecting many pictures, the researchers start to see individuals appearing in different locations at different times.
For example, Spotted Eagle Ray #117, Blitzen, might be seen in May 2020 in Honduras. But in August 2020, Blitzen may be spotted in Mexican waters. We know now that Blitzen migrates from Honduras to Mexico in the summer, and all it took was two photos. Now imagine that with thousands of photos and hundreds of individuals.
Read More: What is a Marine Citizen Scientist and their responsibilities?
By compiling all of this data, the people at The Eagle Ray Project can track individuals. This lets them understand how spotted eagle rays use habitats, if spotted eagle rays are travelling with the same individuals, and where these individuals are migrating.
If you have photos of spotted eagle rays from the Caribbean where you know the location and date, and you’d like to contribute to work that helps save the Spotted Eagle Ray species, you can submit photos to The Eagle Ray Project any time here.
Spotted eagle rays are a majestic species that is in danger of being lost. If we continue to appreciate and learn about them, these magnificent animals can be enjoyed for centuries to come.
To learn more about our author, Anna Ortega and her work, check out her Q&A as a marine science teacher!