Manta rays are ancient creatures, but the species we know today didn’t appear until long after the dinosaurs were gone. Their ancestors were sand-hugging bottom dwellers that looked more like stingrays, and the first true manta rays only emerged about 20 million years ago. So, how did we get from seafloor cruisers to filter-feeding giants? Here’s what the fossil records (and the DNA) can tell us.
Cartilaginous beginnings
The first jawed fish appeared around 450 million years ago. Among them were the ancestors of what we now call cartilaginous fish, which includes sharks, rays, and skates. Unlike bony fish, these animals have skeletons made of cartilage, which is lighter and more flexible than bone.
About 250 million years ago, a major split occurred. One branch led to modern sharks, and the other gave rise to the flattened, bottom-hugging ancestors of today’s rays and skates.
The rise of the rays
Early rays were adapted for life on the seafloor. Their flattened bodies and wing-like fins helped them hide in the sand and sneak up on prey. Stingrays, skates, and other bottom-dwellers came first, and that’s where they stayed for millions of years.
But over time, some rays began venturing away from the seafloor and into the open ocean, and that’s when things started to get interesting.
From seabed to open sea: the mobulid family
Today, there are two recognized species of manta rays: the reef manta (Mobula alfredi) and the giant or pelagic manta (Mobula birostris). Scientists are also investigating a potential third species, the Atlantic manta ray (Mobula cf. birostris).
While pelagic mantas spend much of their lives in the open ocean, reef mantas tend to stay near coastlines and coral reefs, and often within a relatively small home range. But even reef mantas are considered pelagic in a sense, because they don’t rest on the seafloor like stingrays or skates. Instead, they spend their time in constant motion, swimming through the water column, feeding and visiting cleaning stations.
Unlike their benthic (bottom-dwelling) relatives, which hunt small prey along the seabed, mobulids became filter feeders, gliding through the water with mouths wide open to catch plankton.
This transition didn’t happen overnight. Mobulids likely evolved from stingray-like ancestors that slowly adapted to swimming in the water column. Over millions of years, their bodies became more streamlined, their tails lost their stingers, and their head fins, called cephalic fins, became specialized tools for directing food into their mouths.
The first true manta rays
Unfortunately, manta rays (like all cartilaginous fish) don’t fossilize well. Their skeletons are made of cartilage, which breaks down quickly after death. Most of what we have are fossilized teeth, fin spines, or small pieces of cartilage, not the full, graceful body of a manta ray.
The oldest known fossil we can confidently call a manta ray dates back to 20–28 million years ago, during the early Miocene. That might sound old, but keep in mind that dinosaurs disappeared 65 million years ago. So in evolutionary terms, manta rays are relatively new arrivals.
One of the earliest fossil species is Manta fragilis, an extinct manta ray with a lightweight skeleton (as the name suggests). We don’t know much about it, but it helps show that the basic manta ray body plan was already in place by then.
Closest cousins (and some distant ones)
Manta rays are most closely related to devil rays and eagle rays. All three share traits like wing-like pectoral fins, ventral gill slits, and a tendency to swim in open water rather than stay near the seafloor. Devil rays are smaller than mantas, with slightly different feeding habits and body shapes. While still part of the ray family, Eagle rays have distinct snouts and a different diet, often foraging along sandy bottoms for shellfish.
Genetic studies suggest that mobulids (manta and devil rays) split from eagle rays somewhere around 30-40 million years ago. That makes eagle rays more distant relatives, but still closer than anything on the shark side of the family tree.
While sharks are technically cousins too (they all belong to the class Chondrichthyes), it’s a distant relationship. Mantas and sharks do have some things in common: their cartilage-based skeletons, multiple gill slits, electroreception, and their ability to give birth to live pups, something that’s relatively unusual among fish. But beyond that, their lifestyles and body shapes are very different.
Filling in the gaps
Because the fossil record is patchy, scientists use other tools to piece together the story of manta evolution. Genetic studies, for example, show clear links between manta rays and their bottom-dwelling ancestors. Their genes also help explain why manta rays have such large brains, complex social behavior, and unusual reproductive systems.
These traits didn’t appear out of nowhere. They were shaped by millions of years of adaptation to ocean life, first along the seafloor, and later in the open water column.
How old are manta rays compared to everything else?
- First jawed fish: ~450 million years ago
- First sharks & rays split: ~250 million years ago
- Dinosaurs appeared: ~230 million years ago
- Dinosaurs went extinct: ~65 million years ago
- First modern manta rays: ~20–25 million years ago
- First Homo sapiens: ~300,000 years ago
Fun facts about extinct relatives
- Manta fragilis wasn’t fragile in a bad way; it just had a particularly lightweight cartilage structure. In theory, that made it more agile in the water (but less likely to fossilize well).
- Some extinct mobulids had odd-shaped cephalic fins, more like flaps than horns. Over time, evolution refined these into the horn-shaped fins mantas use to help funnel food into their mouths. Today, these fins can be rolled up when not in use and unfurled during feeding.
- Early mobulids may have had partially venomous tails, a trait lost in modern mantas.
Their evolution is a gift, let’s keep it alive
It’s mind-blowing to think about everything manta rays and their ancestors have gone through over millions of years. They’ve survived mass extinctions, shifted from seafloor dwellers to open-water gliders, and evolved into the awe-inspiring creatures we’re lucky enough to witness today. It feels like a miracle that they exist at all.
But manta rays face serious threats and challenges from ocean pollution, fishing and bycatch, unregulated ocean tourism, and climate change. Their slow reproduction makes them especially vulnerable. Their story isn’t over, and it’s up to us to help write the next chapter.
How you can help:
- Reduce your plastic consumption
- Support ocean conservation organizations
- Participate in beach cleanups
- Spread the word about manta rays and why they need our protection
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