Chapter 5: No Substitute for Mom’s Cooking

“Another major milestone began when 501 was about 4 weeks old; she started to shed her bushy pup coat. This fur had made her look more like a cartoon than a real animal. Cute, but at times impractical.”

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A sea otter spends much of its time grooming every part of its fur. Besides eating and sleeping, it’s one of an otter’s most common activities. Around two thirds of an otter’s day is spent on these three behaviors. 

This ultra-fastidious grooming behavior is not neurosis.

Watch a sea otter go through its grooming ritual

Without vigilant hair maintenance, even their extremely dense coats wouldn’t protect them from the cold water of the Pacific Ocean for very long.

Sea otters live where the water ranges from about 35°F to 60°F. For their skin to stay dry and warm in these temperatures, they must continually keep their fur clean, naturally oiled, and full of air bubbles.

They groom their fur with their paws and mouth. This stimulates secretion of natural oils that coat their fur. The rolling and somersaulting that they always do is a way for sea otters to trap tiny air bubbles in their fur.

Otter gets some air during summersaults

These air bubbles provide a very effective layer of insulation, and the sea otters’ natural oils help keep these air bubbles in place.

Chemicals that damage the natural oil of sea otters can kill them. This is especially true for fossil fuel spills. Sea otters also end up ingesting large amounts of fossil fuel as they try to clean their fur, as was the case during the Exxon Valdez oil spill in Alaska.

More than 2,000 northern sea otters died as a result of this catastrophe.

Sea otters are incredibly flexible, so they have no hard to reach spots when it comes to grooming. However, this is the case for sea otters that have already learned how to groom themselves.

For 501, every spot was a hard to reach spot. Learning to groom took time.

Because the only thing 501 could do for herself was poop and sleep and cry—like human babies—sea otter handlers had to take care of all the rest. 

When it came time for a dip in her tank, the risks of hypothermia and drowning still remained. She had to be supervised until she had mastered getting out of the water and onto the haul-out. 

During much of her early time in the ICU, water access was closed off. So she stayed dry on the haul-out. While in the water she could propel herself, but her kicks were uncoordinated and didn’t get her far.

Each time 501 came out of the water, the handlers carefully toweled her dry and then groomed her with a hairbrush, simulating what a mother would do in the wild.

“You’re trying to groom them, and they’re interpreting it as playtime,” Karl Mayer said with a smile. “So they’re trying to bite your hands and rolling around and just basically stimulated. I think that’s what they’d be doing on mom’s chest while she was trying to groom them.”

Two weeks later, when 501 was four weeks old, caretakers introduced solid food to her. 

“We do see pups that will develop gastrointestinal issues with the introduction of solid food,” Mayer said. “It’s a new prey type and neonates, in particular, seem most susceptible. Development of GI problems might cause us to back down and either stop offering solid food, or change our patterns.”

Much like a mother in the wild, caretakers offered her small bites of food. 501 wasn’t always interested, but proving her resiliency again, she handled solid food without any apparent discomfort.

Watch as Otter 501 gets her meal served up

Once the switch to solid foods was underway, she ate between 30 to 35% of her body weight per day.

As an adult in the wild, 501 would eat 25 to 30% of her body weight in food every day. That’s like a 180-pound man having to eat at least 45 pounds of food every day just to maintain his body weight.

But even with all this eating, sea otters don’t have blubber like all other marine mammals. Burning off the calories is another way they stay warm. Sea otters metabolize food nearly three times faster than humans.

Another major milestone began when 501 was about 4 weeks old; she started to shed her bushy pup coat. This fur had made her look more like a cartoon than a real animal. Cute, but at times impractical.

She could roll over onto her belly and she continued to improve her swimming, but her coat was too buoyant for her to dive. 

Shedding occurs gradually, between about four and eight weeks of age in captivity. For 501, the start and end of shedding were both important developmental milestones that the Aquarium staff watched for.  They gauged her progress and looked for signs that she’d be ready for the challenges ahead.

Watch underwater as 501 dives for food

Around the same time, 501 started to look underwater and notice there was a whole other world underneath her. But still she could only bob up and down.

As the days went by, 501 continued to get bigger and stronger while her fur slowly shed.  Her attempts to dive underwater became more frequent and determined.

She began swimming underwater, halfway across her small ICU tank, during a dive. But still, when 501 dove straight down, she kicked like crazy to barely reach the bottom of the tank.

Gradually she became more proficient until she was cruising around underwater and even picking up objects off the bottom.

A closer look at giant kelp

After five days on solid food, at just over four weeks old, 501 was able to pick pieces of clam and squid from a submerged sand bucket in her ICU tank. The surface of the sand was only about a foot and half below the water, far less than she would need to dive for food in the wild, but it was a start.

See as sea otters eat a variety of prey

On July 12th, at five weeks, 501 stopped getting Sea sub-Q fluids. She was eating enough solid food with enough water content to no longer worry her caregivers about dehydration.

She was clearly not fond of being restrained to get shots of fluid under her skin two or three times a day and it certainly wasn’t enjoyable for the caretakers either. Had 501 known she’d be getting a reprieve once she ate enough solid food, she may have eaten more sooner, to everyone’s relief. At this point, her pup coat was 50% shed.

At a little more than six weeks of age, 501 was moved to a bigger outdoor tank for a session in the sun – a big change for a pup who has spent little time in the elements. Typically, first exposure to the outdoors for a pup might be in an ICU-sized tank.

However, maintenance had to be done to her indoor tank, and all that was open was a larger tank meant for adults and groups of otters. To this point, 501 seemed to be progressing at an impressive rate. So the caretakers took a chance. If any pup could handle a shocking new experience, it would be her.

Look how big 501 is now

“They typically tend to be pretty stressed when you put them in a big tank for the first time,” explained Mayer. “It’s a whole different world. She explored the new tank initially and started vocalizing, but stopped and actually seemed to be relatively calm once caregivers left her alone. It seemed like she would vocalize whenever the caregivers went out there to do a feeding or to check on her as if responding to their presence. When she was left alone, she seemed to do pretty well.”

When it came time for release, 501 would have to call upon just that kind of adaptability, swimming free in the sunshine, experiencing the brand new world around her.

See all the milestones 501 is hitting
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You can be a sea otter scientist!

Below are links to webcams from the aquariums of your choice. Spot as many different behaviors as you can.


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Special Features

This Page All

Chapter 1: The Ocean is Cold but Mom is Warm

Chapter 2: Less than Ideal Rescue

Chapter 3: Emergency Treatment

Chapter 4: Species in Danger

Chapter 5: No Substitute for Mom’s Cooking

Chapter 6: The Surrogate

Chapter 7: Furry New Friends

Chapter 8: Release

Chapter 9: A Wild Sea Otter

Video Clip: Grooming Ritual

Watch Toola in a large tank on the roof of the Monterey Bay Aquarium as she grooms her fur. Toola also helped improve 501’s grooming skills. And 501 had to learned to do this well to survive in the wild.

Video Clip: Sea Otter Summersaults

While it may look like this sea otter is just playing, these summersaults actually help the sea otter to trap air in its fur, which helps it to stay warm.

Video Clip: Hand Feeding 501

A caretaker hand feeds 501 in the intensive care unit tank. By banging on shells, the caretaker simulates the sound 501 will hear when she eventually starts breaking open the shells of prey for herself.

Video Clip: 501 Diving for Food

In the rooftop tank now, 501 must learn how to dive and forage for her food.

Video Clip: Underwater Forest of Giant Kelp

Giant kelp (Macrocystis pyrifera) is algae. Holdfasts anchor it to the seafloor, and pneumatocysts, small gas-filled bladders, keep the blades afloat in a canopy that stretches over the water’s surface. Giant kelp can grow to a 100 feet tall. It is also one of the fastest growing organisms on the planet, with a maximum growth of 2 feet per day.

Video Clip: Sea Otter’s Menu

In the wild, sea otters eat many different types of prey. Take a look as some of the things sea otters are eating.

Growth of Otter 501 to 44-days Old

The graph is now extended to show Otter 501’s growth from rescue to 44-days old. Overall, her growth was steadily increasing in just about a straight line. Her feeding time can account for some of the variation in the graph.

Otter 501′s Development to 44-days Old