Considering the immense size of manta rays, it’s clear they’ll have to eat a lot to sustain themselves.
In this article, we’ll dive into what manta rays eat – how much of it they need to eat – and the techniques they use to feed.
Note: I have also recorded a video about this topic. If you would prefer to look & listen, click play to watch the video. If you prefer reading, read on below!
What do Manta Rays Eat?
Mantas eat plankton – more specifically zooplankton. This consists of copepods, mysid shrimp, crab larva, mollusk larvae and fish eggs. Think of an “alphabet soup” of small and microscopic organisms of various kinds and species. Most of them can not or hardly be seen with the naked eye.
There are over 5,000 species of plankton. When you turn on a light in the ocean at night, the plankton makes it look like an underwater snowstorm. Just like moths are drawn to light, plankton is attracted to it as well.
When humans started using big underwater lights that attracted plankton, reef mantas were quick to follow: once they understood that these lights contained more food than any other feeding ground, the manta rays became conditioned to be attracted by the lights as well.
This is how the manta ray viewpoints along the coast of Kona on the Big Island work: these are the locations where manta rays congregate, making them ideal locations for tourists to come and meet the manta rays in their natural habitat. To learn more about the manta ray viewing sites in Kona, check out this article!
Find out more in this article about the effect of night time feeding on manta rays in this article!
How Much Plankton is Needed to Sustain a Manta Ray?
Now let’s calculate how much plankton a manta needs to eat.
Per week a manta ray feeds on approx. 12% of its body weight.
Every foot of a manta ray weights 100 lbs.
For the sake of this example, let’s take a 10 foot manta ray – which would weigh approximately 1,000 lbs (about 450 kilograms)
12% of 1,000 lbs is 120 lbs of plankton (54 kilogram)
A few years ago Kara Osada-D’Avella studied the plankton on the coastline and established that 10,000 pieces of plankton weigh 1 dry ounce.
There are 16 ounces in 1 lbs which concludes that a manta ray consumes (120 x 16 x 10.000) 19,200,000 pieces plankton every week.
This is a HUGE amount of plankton! Mother Nature created not only a beautiful ocean angel but also a voracious creature with one large cavernous mouth ????
In short…
Manta rays swim slowly and gracefully and twirl while they are feeding. Their large mouths open and their cephalic horns unroll to funnel the plankton into their oral cavity.
A manta ray eats 19,200,000 pieces of plankton every week. Kinda mind-boggling, isn’t it?
Related Reading
It goes deeper into the filter-feeding technique they use, but also dives into how they developed specific movements and even collaborate when feeding!
Read more here about the weird and wonderful phenomenon called the Manta Cyclone, in which a big group of mantas get together to feed. It’s a spectacular event, so definitely watch the videos we included in the article!
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