Bears are not carnivores, no wonder pandas eat bamboo

A recent study published in the journal Scientific Reports provides additional evidence that bears, like humans, are omnivores and need much
less protein than zoos provide.

Charles Robbins, a professor of wildlife biology at Washington State University, said: "In the strictest sense, bears are not carnivores, and they don't eat high-protein foods
like cats.
In zoos, polar bears, brown bears or sloth bears are recommended to be fed
as high-protein predators.
As we do, you slowly kill them
.
”

In separate tests, scientists fed captive pandas and sloth bears an unlimited range of foods, observed their preferences, and then recorded the nutritional content
of their chosen foods.

To assess the pandas' preference for bamboo, the researchers collaborated with scientists at Texas A&M University and the Memphis Zoo to conduct feeding studies
on the two pandas.
They found that pandas preferred bamboo stalks to bamboo leaves, and they sometimes ate almost exclusively stalks
.
The researchers also examined data from five Chinese zoos where giant pandas had successfully given birth to offspring, and they found that pandas thrive on a high-carbohydrate, low-protein diet
.

In a series of feeding trials, six sloth bears from Cleveland, Little Rock and San Diego Zoos were offered unlimited avocado, roasted yams, whey and apples
.
They chose almost exclusively fat-rich avocados, eating about 88 percent avocado and 12 percent yams, completely ignoring apples
.
This suggests that sloth bears prefer high-fat, low-carbohydrate foods, which may be similar
to their wild-food termites, ants, and the composition of their eggs and larvae.

It's also very different from
the high-carbohydrate foods they usually eat in captivity.
Native to India, sloth bears typically live only about 17 years in U.
S.
zoos, nearly 20 years
less than the maximum lifespan that can be achieved under human care.
Their most common cause of death is liver cancer
.

The researchers found a similar pattern in previous studies of polar bears, which are typically fed high-protein foods and, if given the choice, mimic the fatty diet
of wild polar bears.
Polar bears in zoos usually die about 10 years earlier than normal, most commonly from kidney and liver disease
.
Both diseases can develop from long-term inflammation of these organs, possibly caused
by years of unbalanced diet.

Both the current study and previous studies have shown that when captive bears are offered dietary choices, they choose foods
that mimic the wild bear diet.

Robbins said: "There is a long-standing idea that humans with PhDs know a lot
more than sloth bears or brown bears.
All of these bears began to evolve about 50 million years ago, and they know
better about this aspect of their diet than we do.
We are the first to ask bears: What do you want to eat? What makes you feel comfortable?"

Robbins is the founder of the WSU Bear Center at Washington State University, the only research facility in the United States that keeps grizzly bears in captivity, and has been studying bear nutrition for decades
.
He and his graduate students first began investigating their unbalanced diets in an Alaskan study, watching grizzly bears eat salmon
.
At the time, researchers theorized that the well-known gluttonous bear would binge eat salmon, sleep, get up, and eat more salmon
.

Instead, they see bears eating salmon, but then wandering around, spending hours looking for and eating small berries
.
Seeing this, Robbins' lab began investigating the diets of grizzly bears living in bear centers and found that they gained the most
weight when fed salmon and berries that contained protein, fat, and carbohydrates.

All eight species of bears, or bears, have a carnivorous ancestor but later evolved to eat a wide variety of foods, which gave them the ability to spread to more areas
without directly competing with local predators.

Robbins said: "This opens up more food resources
than a purely high-protein carnivore.
"

References: "Ursids evolved early and continuously to be low-protein macronutrient omnivores" by Charles T.
Robbins, Amelia L.
Christian, Travis G.
Vineyard, Debbie Thompson, Katrina K.
Knott, Troy N.
Tollefson, Andrea L.
Fidgett and Tryon A.
Wickersham, 9 September 2022, Scientific Reports.