Visitors to the Marin Headlands must be wondering about all the strange noises coming from the hillside above Rodeo Beach these days. The howls, cackles, barks and roars that echo across the hills must seem puzzling and mysterious coming from such a peaceful location.
May 14, 2014
For the curious who venture to take a closer look, the source of this noise can soon be discovered. The cacophony, of course, is coming from our patients here at The Marine Mammal Center. This is our busiest time of year, and we are experiencing a record-breaking number of patients this year.
We currently have more than 160 patients on-site, most of them elephant seal pups and sea lions, along with a few dozen harbor seals. The noise they make can be heard reverberating across the Marin Headlands.
Elephant seal pups, like human babies, make noise for a reason. It is primarily a way to let their mothers know they are hungry, but it is also a survival mechanism. Immediately after birth, a mother seal learns to recognize the distinctive cries of her own pup and this helps the two of them stay together. This is especially important in crowded rookeries, where surf conditions are rough, territorial disputes are frequent, and battles between males can send animals scattering in all directions.
When they are older, elephant seals start to make different vocalizations (find out what they sound like!) that serve other purposes. An adult male will let out a deep guttural grunting sound that asserts his dominance to other males on the beach. The sound emanates from the throat, larynx and chest, and can be amplified by inflating the long elephantine nose, or proboscis. It is sometimes modified to a slow knocking or clicking sound, which can often be a prelude to a fight.
Year after year, elephant seal males can recognize the distinctive acoustic signature of a particular alpha male. This is another survival mechanism, allowing the animal to make the critical choice to compete or retreat. Conserving vital energy is an important consideration for elephant seals, so the information gained from vocalizations helps them evaluate threats or challenges.
Vocalization in sea lions (find out what they sound like!) also has an important purpose, playing a critical role in the bond that develops between a mother and her pup. Dr. Frances Gulland, the Center's senior scientist, took part in a study of this phenomenon entitled Filial Imprinting in a Steller Sea Lion (Eumetopias jubatus). The study examined the ways that "Otariid [sea lion family] mother-pup pairs identify and locate each other on the rookery through the exchange of unique stereotyped vocalizations as well as with visual and olfactory cues at close range."
Harbor seal pups have a unique vocalization (find out what they sound like!), one that is remarkably different from elephant seals and sea lions. Their mothers quickly learn to recognize their distinctive and plaintive cries of “Mah, mah!” This heart-rending call often leads well-meaning beachgoers to mistake a lone harbor seal pup for an orphan. In most cases, though, the pup is just waiting for its mother to return from a shopping trip to the ocean. During pupping season in the spring, The Marine Mammal Center makes a concerted effort to spread the word about this, encouraging the public to Leave Seals Be.
The evocative cries of elephant seals and sea lions have figured prominently in a number of blockbuster movies. In a 2010 interview with Designing Sound, Sound Engineer David Farmer described how he came to use the howling of elephant seal pups in The Lord of the Rings:
“One day, my wife and I happened to be at The Marine Mammal Center in the Marin Headlands, and it was the time of year they had lots of baby elephant seals there, and a few of them were very vocal. I’d never heard that sound before and knew that would be perfect for the Moria Orcs.”
Farmer also recorded the barking sea lions at the Center, transforming their vocalizations into the voices of the more savage Uruks. Other sound designers have visited the Center and recorded our patients, including Randy Thom, director of Sound Design at Skywalker Sound. Thom used a unique combination of sounds to give voice to Toothless, the baby dragon in How to Train Your Dragon.
“Toothless was the biggest challenge for us in terms of the vocalization, because he had to have so much variety just within his own voice,” Thom said, describing the process of combining his own voice with recordings from elephant seals, horses, tigers and other animals.
Come visit The Marine Mammal Center and listen for yourself how our pinniped patients vocalize.
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