Are manta rays fish or mammals? Do they lay eggs?

From their majestic wings to the unique way they reproduce, manta rays are one of the most fascinating creatures in our oceans.

But how do these gentle giants of the sea reproduce? Are manta rays fish or mammals? Do they lay eggs, are manta ray pups born alive, or is it something else entirely?

Let’s dive into manta ray reproduction and explore where little manta rays come from!

Are Manta Rays Fish or Mammals? Manta Ray Classification

First things first, let’s not keep you waiting: manta rays are most definitely fish.

They belong to a group of cartilaginous fish called Elasmobranchs, which include sharks, rays, and skates.

When most people think of fish, they first think of “bony fish”: the skeleton of most fish is composed of bones.

However, Elasmobranchii are cartilaginous, which means their skeletons are made of cartilage instead of bone. The cartilaginous skeleton gives manta rays and their fellow elasmobranchs even greater flexibility than other types of fish.

There are two types of cartilaginous fish: elasmobranch and holocephalans.

The main difference between holocephalans and elasmobranchs (and this is where we get to the point) is that while holocephalans lay eggs, elasmobranchs (including mantas!) give birth to live pups.

This makes them rather special!

How the Eggs of a Manta Ray Develop: Inside their Body

There’s one word I usually avoid when talking about manta rays, even though it’s an important part of what mantas are: “ovoviviparous”. You try and say that aloud five times in a row!

Unlike many other species that lay eggs outside their bodies and fertilize them externally with sperm from another fish, ovoviviparous fish (like mantas) produce eggs within their bodies that hatch while still inside the mother.

This means that when it comes time for birth, the babies are fully developed and ready to be released into the ocean!

Examples of ovoviviparous animals are several types of snakes, some salamanders, etc.

During mating season, manta ray males will compete with each other for access to females in order to fertilize her egg sac. Read more here about the mating rituals and techniques of manta rays!

After the egg is fertilized, the female manta ray will carry it inside her body for 12-13 months before giving birth. Manta ray embryos develop into pups and eventually emerge as fully-formed mini-mantas from the mother’s body. Once born, the pup can measure up to 50 inches (130 cm) tip-to-tip and weigh over 20 pounds (9kg)!

No post-care is available to the pup [yep, they are on their own right away!], but the female manta ray provides her developing pups with nutrients and protection from predators until they are ready to go out into the ocean.

We don’t know this for sure, but assume that a manta ray female can carry two pups in her womb at one time, although the birth of twins is extremely rare; two pups would take up so much room inside the mother! It is more common for them to give birth to just one manta ray baby at a time.

This fascinating article tells us more about the evolution of the manta ray pup inside the womb, according to studies conducted in aquariums around the world.

The Birth of Manta Ray Pups

If you’ve read my other article (and seen the pictures) on the topic, you already know that manta ray babies come out of their mother wrapped up like a burrito. The birth wrinkles of a manta ray pup are adorable!

When a baby manta ray is born, it looks just like a grown-up, except it’s a lot smaller. It’s fully formed and ready for life in the open ocean.

In addition to having long gestation periods, female mantas produce offspring infrequently: they may only reproduce every 2-5 years depending on environmental conditions such as food availability and water temperature.

This low reproduction rate, combined with the many dangers that loom out there for manta rays, led to them being classified as an endangered species. Our human curiosity and desire to know more about these mysterious animals is just one of many reasons we do what we can to protect the manta rays of Hawaii.