Study: Manta Rays Can Breathe Inside The Womb

A rare ultrasound scan of a mother Manta Ray revealed that their babies can breathe in the womb. Researchers at the Okinawa Churaumi Aquarium in Japan found this and many other fascinating facts after they looked after a pregnant Manta Ray.

The manta rays can grow to up to 16 feet wide but despite their size marine biologists have not been able to gather much information about the species.

Until 2007 it was not even known as to how long the pregnancy of these marine mammals lasted. That year, a baby manta ray was born into captivity for the first time, after gestating for a year and nine days, according to the conservation group MantaWatch

Experts also found that unlike other mammals Manta rays do not have a placenta or an umbilical cord. Therefore their fetuses need to get nutrients from the mother in a different way.

The new study, which was published in on 5th June in the journal Biology Letters sheds more light on Manta ray pregnancies.

Researchers at the Okinawa Churaumi Aquarium in Japan had captured a Manta ray off of Okinawa halfway through her pregnancy. The female offspring was born in October 2009 and while she was inside the womb, the researchers had been able to take ultrasound scans to study the development stages.

They found that the fetal Manta ray repeatedly opened and closed her mouth inside the womb. This process is known as buccal pumping. On land, frogs and toads also display a similar breathing action when they expand their throats to take in air. But in the case of manta it was not breathing air but the uterine fluid.

Anatomical changes that happen around birth seem to allow baby manta rays to transition to pulling oxygen from water rather than from the uterine environment, the researchers reported.

They also added that the behavior was similar to the other rays that hatch from eggs and pull in oxygen flowing through their egg sacs.

Live born Manta rays, however, not only breathe in oxygen from the fluid but also drink it and it is the only source of nutrient for them, the researchers suggest. When still born mantas were studied, the uterine fluid was indeed found to be present in their digestive tract.

As of 2009, the baby ray in the study had grown to more than 286 pounds (130 kilograms) and had a wingspan of almost 7 feet (2.1 meters)

Manta rays are widespread across the world oceans but they prefer tropical and subtropical climates. Because the species has many subpopulations and are hunted to be made into Chinese medicines the International Union for Conservation of Nature has named the species vulnerable.