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  • Kelly Carpenter

Creature Feature: Spotted Eagle Rays

A spotted eagle ray searching the sandy bottom for its next meal (photo: Dan Schofield)

One of the most exciting and graceful marine animals to see underwater is the incredible Spotted Eagle Ray (aetobatus narinari). We are so lucky to have them in our waters here on Grand Cayman and there is a thrilling, humbling feeling that comes with watching these beautiful creatures glide through the water. Spotted eagle rays are well recognized and much loved - so much that you can frequently find them in art, dive appareltattoos, and even Disney movies!


In all honesty, I thought this would be an easy blog post to write - spotted eagle rays are so popular that there has got to be tons of information about them online right?? Boy was that wrong…in my research for this post I was surprised to find spotted eagle rays are actually an understudied species. There isn’t enough data available to determine facts like where exactly they live, where and how they migrate, feeding habits and more. Even the exact lifespan of spotted eagle rays isn’t known! What details I could find about these majestic creatures I’ve collected here, and included some amazing photos and super fun facts for you all to enjoy.



Fun fact #1 : The genus name Aetobatus comes from the Greek word aetos meaning ‘eagle’ and batis meaning ‘ray’


Features

Spotted eagle rays are easily identified by their diamond shaped body, which is white on the bottom while the dorsal (or top) side is dark with a stunning pattern of white spots and rings. The spot patterns are as unique to each individual as fingerprints are to humans, and computer programs can be used to analyze the patterns to identify individual rays.


Spotted eagle rays also have a long whip-like tail with venomous barbs at the base for protection from predators. Their tails can be up to three times the length of their bodies! Spotted eagle rays are larger than I was expecting - they have been measured at over 16ft long including the tail, and almost 10ft wide tip to tip. The max recorded weight is over 500 pounds! (For those using metric, that’s up to 5m long including the tail, 3m wide and a max recorded weight of over 230kg!)



A spotted eagle ray swimming mid-water. Look how long the tail is!

Fun fact #2 : While the venomous barbs on their tails can cause serious wounds, spotted eagle rays are not considered dangerous to humans (unless they are caught and handled incorrectly of course)


Habitat

Spotted eagle rays can be found in coastal areas, in tropical to warm waters. They mostly live around coral reefs close to shore, although they can sometimes also travel in the open ocean and even inland in estuaries and protected bays.


The aetobatus narinari species of spotted eagle rays is found in the Atlantic Ocean - from North Carolina to as far south as Brazil, and including the Caribbean and Gulf of Mexico. This species is also found along the western coast of Africa, although due to severe population decline the exact range is not known.


A lone spotted eagle ray cruising over the reef

Behavior

As many of you know, spotted eagle rays spend much of their time swimming in mid-water, moving their body like ‘wings’ to glide through the ocean. They frequent muddy and sandy bottoms to search for prey, and have been observed at depths up to 196ft / 60m!


While spotted eagle rays are usually solo creatures, they are sometimes found together in small groups around coastal reefs. They have even been known to gather in large schools to cross the open ocean!


If you’ve seen a spotted eagle ray underwater, it was mostly likely from a bit of a distance. These docile creatures are generally pretty skittish, they are wary of divers and quick to swim away if you start to approach. This makes it all the more special if you are lucky enough to see one up close!



Fun fact #3 : Eagle rays world-wide have been observed jumping out of the water! While the exact reason is unknown, possible reasons are to avoid predators or unwanted mates, to shake off parasites or remoras, or maybe even just for fun! To see a video of this remarkable behavior in a similar species, check out this YouTube video from the Smithsonian Channel. The breaching starts at 1 minute 45 seconds.


Feeding

Spotted eagle rays are considered foraging predators. They use their duck-like bill to sift through mud and sand on the ocean floor to find a tasty meal - including clams, oysters, sea urchins, crabs, shrimp, octopus, and even small bony fish!


Instead of rows of teeth or bristles like many sharks, spotted eagle rays have just two broad, flat teeth plates that sit on the top and bottoms of their mouths that they use to crush the shells and bones of their prey. You can find a picture of an eagle ray jaw bone and teeth plates here.


Predators of this majestic species are mostly sharks, including tiger sharks, silvertips and great hammerheads.


A spotted eagle ray searching the sea floor for a snack

Reproduction

Spotted eagle rays reproduce together in mid-water, and have a gestation period of 12 months. Each litter can have between 1 and 5 pups. Eagle rays are ovoviviparous, meaning the eggs develop and hatch inside the mother’s body, where they feed on the egg yolk until birthed. Other ovoviviparous animals include some snakes, some fish including guppies and seahorses, and some sharks including tiger and great white sharks!


Check out this unbelievably adorable video from KUTV 2News of the birth of two baby spotted eagle rays. (I’ve watched this video dozens of times since it was first posted, it’s actually the inspiration for this post!)


Fun fact #4 : The lifespan of eagle rays is not actually currently known. What is known is the generational length (the time from birth to reproduction), which is about 10 years


Species recent reclassification

This is probably my favorite fact I learned about spotted eagle rays during my research, I think it is so cool!


Spotted eagle rays were originally classified as a single species worldwide, since their initial classification as the Aetobatus narinari in 1790. However in 2009 to 2010, research papers were published that reclassified spotted eagle rays into two different species! The spotted eagle ray species we are familiar with here in Cayman is the original Aetobatus narinari, which is found in the Atlantic Ocean. The Indo-Pacific spotted eagle ray is actually a different species, Aetobatus ocellatus. There might even be a third species, but more research is still needed. For more details you can request full copies of the research papers here and here.


IUCN Threatened List

The International Union for Conservation of Nature (IUCN) was established in 1964 and has become a global leader in tracking the conservation status of animals, fungus, and plant species.


Spotted eagle rays were considered “Near-Threatened” by the IUCN for many years. However as of 2020 with the recent species reclassification came new data which now lists our beloved spotted eagle ray as “Endangered”, as there is a suspected overall population decrease of 50-79% over the last 30 years.


Threats to spotted eagle rays are mostly from human behavior, specifically fisheries as these beautiful rays are sadly frequently caught as bycatch.


Conservation

The good news is that there are ongoing global efforts to study and protect our beloved spotted eagle rays. These creatures are protected in Florida, and in 2012 the Bermuda government made eagle rays a Level 1 protected species. Groups such as the Save Our Seas Foundation and the California Academy of Sciences are also working to better understand the population and habits of these creatures in order to put better protection plans in place.


You can even help with spotted eagle ray conservation! If you see a spotted eagle ray, simply fill out this online form from the Mote Marine Laboratory & Aquarium (or email rayreports@mote.org). They use your information to better understand and evaluate the status of spotted eagle rays in the wild.



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