Hee, hee. Did you know manta rays have a social life? I know about manta rays social lives because I AM a manta ray. My name is Molly. Humans have only studied manta rays in depth (probably) for decades. Before we were admired for being a gentle giant, fishermen called us “devilfish.” Our curled up head fins look like devil horns, hence the name. Never mind most of the time we’re feeding and our cephalic fins are uncurled. We’d often get caught in fishermen’s nets by accident. The fishermen would get angry that not only did they have to untangle us, but they often had to repair their nets.
In any case, humans have come out with a research study showing that female reef manta rays (Manta alfredi) “show preference” to other female manta rays. I’d say we’re friends, or acquaintances at least for the short-term. We also remember our contact with each other.
We form bonds with other female manta rays over weeks and months but not necessarily longer. That’s okay as many times after a feeding frenzy, or a stop at a cleaning station, we go our separate ways. We don’t vocalize like whales, who keep in touch at long distances. When we get excited socially we can brighten the white splotches on our black backs. But we do have the largest brain-to-body ratio of any fish so it’s no wonder we can use some of our brainpower to recognize others.
The boys, well they’re on their own unless they group with other males, females and juveniles. The main times we all come together are for feeding (plankton for all!), at cleaning stations (ahh…), and for mating. A train of males will trail a female for a long time until she gives in and mates with one. It’s fun, up to a certain point. Who doesn’t like all that attention?
So although scientists study manta rays social lives, we are in trouble nowadays because of our gill rakers. The very body parts that keep us alive are now threatening our lives. Gill rakers are a covering on my gills, which not only help me breathe, but also feed. The gill rakers act like strainers. They filter ocean water as I swim. Plankton in the water stick to the gill rakers. Plankton are the tiny plants and animals that live in the ocean and are at the bottom of the food chain. The plankton builds up on my gill rakers and yum, time to swallow!
Unfortunately many humans covet our gill rakers for the Traditional Chinese Medicine market. There is no traditional formula that contains manta ray gill rakers, just a controversial new one.
I only have 1-2 pups every 2-5 years. That’s not very often, and we certainly can’t keep up with the fishermen killing us.
Other threats to manta rays, which are making us become endangered, are injuries from being entangled in discarded fishing nets, pollution (especially microplastics) and habitat destruction.
For more information on how you can help visit:
Paper published on 22 August 2019: Rob Perryman et al, “Social preferences and network structure in a population of reef manta rays” Behavioral Ecology and Sociobiology
Also see Meet the Pink Manta Ray