BRIGANTINE, NJ – If you take a trip to the beach this time of year, you have a very good chance of spotting a seal swimming in the ocean or lounging on the beach. You might also notice some of those seals have pink numbers spraypainted on them.
No, they’re not participants of a seal marathon race, those numbers help wildlife management workers know who they are and where they come from. They’re put there intentionally by workers at the Marine Mammal Stranding Center.
“It’s a call we get a few times every seal season. Ever wonder about the seals with the pink or orange markings? Today we are unraveling that mystery,” The Marine Mammal Stranding Center said. “When our Stranding Team needs to relocate a seal to a new location due to disturbance, we mark them so we know they have been assessed by our staff to be healthy enough to return to sea.”
The center said each seal will have a specific number written on their head or back with a non-toxic livestock marker in a bright pigment that fades in a few weeks.
Having a bright pink mark on your back in an ocean full of predators and sharks might not be helpful to the seals, you would think.
The MMSC said it’s not a problem, because sharks can’t see the color.
“If the same seal shows up on another beach, the number lets us know that we have already checked on that animal,” the MMSC said. “People often ask if the marking makes the seals more vulnerable to predation by sharks. Sharks are believed to have only one type of cone (green-sensitive) whereas humans have three (red, green and blue sensitive), enabling us to tell the subtle differences between a wider range of colors.”
Since sharks are lacking in the ability to detect red, the pink or orange pigments likely have little contrast against a seal’s grey or brown coat. Sharks also typically make their approach on seals from below in a sudden vertical rush, rather than from above.
You can learn more about the Jersey Shore’s marine mammals at Marine Mammal Stranding Center.