Spotted Eagle Rays
Highlights
- Scientific Name: Aetobatus narinari
- Status in the Wild: Threatened
- Habitat: Oceans
- Diet: Carnivore
Spotted eagle rays, also known as bonnet rays, are a magnificent diamond-shaped species that can be found among coral reefs and shallow tropical waters all over the planet. In Costa Rica, these fish are easily identified by the perfectly spaced white dots over deep blue or black dorsal bodies. Markings can vary, and in different parts of the world the dots are often replaced by white rings. Other prominent features include smooth white underbellies, beak-like heads and respiratory spiracles – orifices that pump water over the gills – on both sides of the skull. Their wings can span almost 10 feet, and the heaviest ray on record weighed in at a whopping 507 pounds. Their cartilaginous bodies can measure 8.2 feet in length, and their whip-like tails add an additional 8.3 feet – for a maximum total of 16.4 feet. Exact lifespan is unknown, but is estimated to be about 20 years.
read more closeWhen hunted, spotted eagle rays are able to spring completely out of the water in an attempt to escape. Long, flexible tails equipped with two to six venomous spikes serve as the creature's only defense mechanism. While these rays are non-aggressive and generally avoid human contact, they can be considered dangerous if threatened by divers that get too close – their toxic tail spines can inflict serious injuries.
Boasting one of the highest brain-to-body-weight ratios in the world, spotted eagle rays are thought to be highly intelligent beings with intricate social patterns. Their diets consist of clams, mollusks, shrimp, oysters, sea urchins, squid and bony fish. Their bill-shaped snouts are perfect for shoveling sand and foraging for food in rocky nooks and crannies. Additionally, electroreceptors enable the animals to detect faint currents emitted by the muscles of their prey. The rays then use nipple-like papillae located on the underside of their mouths to remove indigestible shells before crushing their prey with a pair of wide, V-shaped plates that function as teeth.
Habitat:
Spotted eagle rays inhabit both Atlantic and Pacific waters – from North Carolina to Brazil, and from the Gulf of California to Peru. They are also observed in the Red Sea, South Africa, Hawaii, Japan and Australia. In Costa Rica, they are most commonly spotted off the west coast – in diving hotspots like Playa del Coco, Cano Island, and Cocos Island. Neither nocturnal nor diurnal, spotted eagle rays live their lives according to the tides. At high tide they socialize, hunt, and mate – while at low tide they like to rest in groups. Unlike many species of rays, spotted eagles do not spend most of their time relaxing on the sea floor. Instead, they prefer to soar gracefully throughout the open ocean, propelled by the undulation of their pectoral fins. These creatures stick to shallow waters no deeper than 260 feet, and can be found in schools of 3-100 individuals.
Reproduction:
Spotted eagle rays are ovoviviparous, meaning their eggs develop and hatch within the mother's body but are sustained by a yolk sac instead of a cord to the placenta. Rays reach sexual maturity at four to six years of age, and between one and four pups are produced per live-birthed litter. The reproduction ritual entails one or more males pursuing a female, biting and nipping at her pectoral fin. The actual mating lasts for only 20-90 seconds, and females have been observed mating with up to four males in a very short period of time. Gestation time is about 12 months before females give birth, jumping and flipping above the water in an effort to help expel their young.
Status in the Wild:
Spotted eagle rays are currently in the lower risk/near threatened category on the IUCN Red List. Overfishing is the most alarming human hazard to the species. Due to the poor quality of its flesh, the spotted eagle ray is rarely eaten. Instead, it is used for oil and fishmeal. Natural predators include white tip, tiger, bull and hammerhead sharks. Certain parasites can also pose a threat to their well-being.