Getting to Know You
By: Emily Laughnan
Spying on your neighbors, taking their pictures at their favorite hangouts and referring to books about human anatomy doesn’t really count as getting to know them. Likewise, taking aerial photos of manatees, following them to their favorite habitat and studying their remains is only the beginning of discovering what drives them to behave as they do.
Mote researchers wanted to get to know manatees better — and they have been. They’ve been studying manatees in the wild for two decades. And since 1998, with permission from the U.S. Fish and Wildlife Service, trainers at Mote have been working with resident manatees Hugh and Buffett — captive-born half-brothers who share a 70,000-gallon aquarium habitat — to gain their trust and teach them how to respond to commands.
The goal is to condition Hugh and Buffett so they can teach scientists and resource managers how manatees in the wild communicate and perceive their world. That in turn will help humans monitor their own behavior around the animals in the wild, said Dr. John Reynolds, manager of the Manatee Research Program at Mote. “For example, if they’re homing in on chemical cues to locate freshwater sources, and we add chemicals to the water, that may affect their ability to find an important resource they need,” he said. “Or we’ll know that if we make a particular type of noise, it could disrupt a mother’s ability to sense her calf.”
The Mote team first trained Hugh and Buffett to perform basic tasks, then began studying their eye-sight, whisker sensitivity, body temperature and, in the latest study, their ability to detect the direction of sound as it moves through the water.
Understanding a Manatee
Hugh and Buffett, like many brothers, focus better apart so they don’t distract each other. Five mornings a week, they take turns working with Mote’s research team in a special area of their habitat. Here, trainers reinforce correct behaviors with toots from high-pitched whistles and watch as a gray, whiskered nose pushes above the surface, to pull air through nickel-sized nostrils or wait for a treat.
An assistant records data on a towel-lined computer at one edge of the habitat and another trainer reaches out and gently scratches Hugh’s back. He’s the more energetic brother, she says, and it’s harder to keep his attention for an entire session.
“It’s really neat for Mote because we’re the only ones that have the animals trained to this point. There are other facilities that have permits to train their animals for different things, but nobody’s doing exactly what we’re doing,” said Debi Colbert, who coordinates Mote’s resident manatee research.
The research continues with a few more blows of a whistle and, of course, sweets for reinforcement. Rosy red beet chunks, baby carrots, apple wedges and monkey biscuits get Hugh and Buffett through the more rigorous exercises.
The Mote team first taught Hugh and Buffett how to respond to cues in 1998. The cues helped train the brothers to allow researchers to measure certain basics — like lengths and girths, temperature, urine and blood parameters. Trainers taught them how to float in different positions on command and, over the course of a year, the manatees learned how to respond to different touches, sounds and signals. Learning those basics has led to today’s in-depth research designed to help humans gather more information about Hugh’s and Buffett’s senses.
“What we’re working on is a pretty detailed project, working with the different senses of the manatee,” Colbert said.
Asking Deeper Questions
These days, Hugh and Buffett are training for an upcoming study to help researchers measure their ability to detect the direction that sound is coming from. This “sound localization” study involves speakers that play various sounds underwater. The sounds — purposely chosen to be within their hearing range — are piped into the training tanks from four speakers.
In training, if Hugh and Buffett swim toward the right sound source, they get a treat. So far, they’re swimming toward the right targets and so hinting to researchers that they are able to localize the sounds being tested. “We didn’t know that manatees could localize sound at all. A very big question with the boater community right now is one, can they hear sounds in the frequency range of boat engines and, two, if they can, can they tell where that sound’s coming from?” Colbert said. “(Humans) use the time difference between our ears to localize where sound is coming from in air. Under water, the sound is so much faster that you can’t tell the difference. So if you’re a scuba diver, somebody could be banging on the tank beside you and you’d be looking all over the place. You can’t tell where the sound comes from. We don’t know if manatees can tell where the sound is coming from or if they can localize sound.”
Mote scientists are planning future studies focusing on the manatees’ sense of touch because the mammals have limited eyesight and probably use other senses to feel what’s around them. In 2003, the team published a report showing that a manatee’s blueberry-sized eyes probably orient them and help them sense objects far away, but touch helps them gain more details about their immediate surroundings — this possibly includes the detection of pressure waves that low frequency sounds from mechanical noises can produce.
Hairs poke through the leathery skin all over a manatee’s body. While they aren’t immediately obvious, they form inch-long bristles spaced at least its length apart. The waves in the water may brush past these hairs and trigger nerves, which may help manatees locate the direction of the waves, researchers say. While scientists have conjectured for the past 30 years that this was happening, the Mote studies are offering much better insight.
“It essentially becomes those pressure waves, those sounds, that create water movements. They can’t actually hear the sounds, it’s totally physical,” said Joe Gaspard, who directs the manatee training at Mote.
Discussing Challenges
Another study with Hugh and Buffett is trying to answer more questions about how the animals produce heat.
“Manatees are herbivores that use microbes like bacteria to break down the plant material, or cellulose, they eat, which produces heat as a byproduct,” Reynolds said. “Have you ever walked into a cow barn or a horse barn on a cold day? It’s warm in there. The animals generate their own body heat — as all mammals do — but the breakdown of cellulose produces additional heat. We think that manatees are getting a lot of their needed heat from the cellulolytic bacteria that are breaking down the plants as part of the digestive process. Since manatees have an extremely low metabolic rate for an animal their size, this heat is likely to be extremely important to the animals’ ability to survive. It’s like having a large internal furnace.”
But this may not always be enough for Hugh’s and Buffett’s wild relatives, so they seek warmer waters to congregate in during winter when Florida waters cool. Aerial photographs show the animals’ mass, winter migration to natural springs and to the warm-water discharge stations at power plants, where they cluster by the hundreds. But the waters around power plants may lack sufficient food.
“In winter, what we fear is happening is that the animals migrate a long way without eating to get to the power plants. And if there’s no food there, their internal furnaces may get turned off,” Reynolds said. “Then, that loss of an internal heat source may compromise the manatees’ survival when they venture out into cold water.”
As power companies discuss closing some plants, Reynolds wonders if the manatees will be able to adjust to the loss of warm waters. The thermal studies on Hugh and Buffett may be among the most important for managing their wild relatives. “Probably the biggest conservation issue facing manatees in the next 30 years is going to be the loss of warm-water refugia,” Reynolds said.
With these advanced studies on resident manatees like Hugh and Buffett, researchers are just beginning to understand them better and even imagine the world through their senses. Researchers at Mote say they hope other scientists will train manatees for new research that could be crucial to the species’ survival.
“It’s a really neat thing, it’s cool, what we’re doing. But it’s the tip of the iceberg. We need to be doing more studies with more animals to get a better understanding of these issues,” Colbert said.
Learn more about: Manatee Research
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Mote Marine Laboratory has been a leader in marine research since it was founded in 1955. Today, we incorporate public outreach as a key part of our mission. Mote is an independent nonprofit organization and has seven centers for marine research, the public Mote Aquarium and an Education Division specializing in public programs for all ages.
