How Pet Food Developers Whet Furry Appetites


Untreated, a piece of dry kibble is largely flavorless. Made of various meals and fats and blended with wheat and soy grains to offer balanced nutrition for an animal’s body, it would fail to stir the interest of most domesticated pets. Dogs might eat it without enthusiasm; cats would let it grow stale on the floor. Indifferent to grains, they need some extra incentive to empty their bowls.

That’s where Nancy Rawson, Ph.D. comes in. The Associate Director of the Monell Chemical Senses Center in Philadelphia, Rawson is an expert in tastes and flavors relating to research palatants—additives that give bland foods their taste appeal—for both humans and animals alike.

“[Food companies] want to bring the pet to the bowl,” Rawson tells mental_floss. “Dog food companies are good at formulation, but look elsewhere for their flavor systems.”

A large part of the work of places pet food companies consult with--one, AFB International, was where Rawson worked from 2010 to 2016--is focused on developing coatings that will make pets enthusiastic. For cats, the results of a hit recipe might mean whining and weaving in between their owner's feet until dinner is served. For dogs, it might entail getting so excited that they eat too quickly and bring the food right back up.

“I wouldn’t say puke is a good sign,” Rawson says. “But it can mean dogs really like the food.”


After subsisting on table scraps or the carcasses of dead livestock for thousands of years, domesticated dogs and cats started enjoying commercially produced canned food beginning in the 1920s. (Dog biscuits were invented in England in the mid-19th century, but only found favor in wealthier families.) The first canned food was Ken-L-Ration; those who opened a tin were likely to find wet food consisting largely of horse meat.

The demand for ready-to-serve dog food—cats were a minority interest for the companies at that time—grew so much that the Chappel brothers, owners of Ken-L-Ration, started breeding and slaughtering up to 50,000 horses a year for the purpose of putting their remains in cans. Horse meat became a less common ingredient by the 1940s, replaced with other kinds of meat, but with the outbreak of World War II, the rationing of both meat and tin meant that wet food in general grew scarce. Pet owners turned instead to the enormous stacks of dry kibble, which had first gone on sale in 1928 in 100-pound bags.

It was breakfast cereal that ushered in the modern age of marketable chow. In 1950, Ralston-Purina, which made both pet food and human-grade foods, developed an extrusion process in which they could shape their grains into air-puffed shapes that would hold up to submersion in milk. Purina’s dog food division took notice, spent three years tinkering with the extrusion machine, and then released Purina Dog Chow in 1957 to great acclaim. Easier to digest, with a fatty coating and texture made possible by extrusion, it marked the first time food companies treated a dog’s palate as worthy of consideration.


With $22 billion in sales in 2014, pet food companies are using some exacting science and research to make sure their kibble is worth binging on. For that, they outsource to companies like AFB and Kemin, home to flavor experts who develop the palatants designed to appeal to a pet's appetite.

Because canines and felines are non-verbal, Rawson is an expert on using bowl tests to assess the appeal of various dry food palatants—made from chemical blends, soy, corn, and animal organs blended into powder or liquid form [PDF]—using bowl tests. (Wet food, while it can contain palatants, is often flavorful enough on its own.) Animals at AFB are presented with two different meals and measured on criteria such as how quickly they come to the bowl, which bowl they indulge in first, how long they take to empty it, whether they stop and come back, and in some cases, how much time they spend with their nose buried in food relative to how long the food was available. This metric, for dogs, is called the Nose in Bowl, or NIB, test [PDF].

“You kind of have to treat them like babies,” Rawson says. “They can’t respond in words, so you pay attention to their behaviors.”

Cats, Rawson says, are reliable addicts for polyphosphates, an additive that she likens to the salt humans pour over their food. Cats also prefer the easy breakage of X-shaped kibble over other shapes, meaning that fun extrusions aren’t just for human amusement. “Cats don’t have molars, so different shapes break into different sizes more easily.” X-shaped pellets are easier for them to chew.

Dogs, on the other hand, aren't nearly as choosy. “We did a study and found that dogs will eat the largest size of kibble, regardless of breed,” Rawson says. A more important goal in designing dog food, both in terms of palatants and food density, is cleaning the dog's teeth, as well as slowing them down so they don't eat too much at once.

“Dogs are pleasers,” she says. “They’ll eat a bowl of rocks if their owner puts it down in front of them. The palatants act as more of a preservative for the food.”

And while dogs focus on smell, the aroma coming from an open bag isn't strictly for them. When owners open a chicken or fish-flavored meal, Rawson says, a lot of that smell and presentation is meant as much for the human as their pet. If AFB indulged only in what drove dogs crazy, like compounds given off by decomposing protein, their owner would never buy a second bag.

“When you open a bag of chicken kibble, you want it to smell like chicken. The job of the palatants companies is, in a way, to serve two masters.”


For pet food experts like Rawson, how food exits an animal is almost as important as how well it’s enjoyed on the way in. Dyed food, while festive for owners, turned out not to be such a good idea when your cat barfs up a rainbow on the carpet.

Palatants can also incorporate stool-hardening agents to make clean-up easier. Ever wonder what makes certain chow puppy-appropriate? Aside from calories, it’s partially an ability to reduce loose stools in younger dogs. Companies are "always trying to optimize stool volume,” she says. Reducing odor is also key, and certain formulations can do a better job of that than others.

Recently, the pet food conglomerates have been eyeing the growing demand for food that resembles human-grade servings. Purina now offers premium meals containing rotisserie chicken and filet mignon and employs a full-time pet food chef.

For Rawson, the movement into food that could conceivably co-exist on both a dog’s and owner’s plate isn't one worth embracing. “One of the fundamental problems is one of sustainability,” she says. “We’re diverting millions of tons of chicken meat into pet food that could be going to humans. Pets evolved eating guts. That’s what we should be using.”

14 Bold Facts About Bald Eagles

Bald eagles are powerful symbols of America—but there’s a whole lot more to these quirky birds.


A young bald eagle with a brown head on a beach.

So obviously adult bald eagles aren't really bald, either—their heads have bright white plumage that contrasts with their dark body feathers, giving them a "bald" look. But young bald eagles have mostly brown heads. In fact, for the first four or five years of their lives, they move through a complicated series of different plumage patterns; in their second year, for instance, they have white bellies.


A red-tailed hawk.
A red-tailed hawk's screech is usually dubbed over the bald eagle's weaker scream.

It's a scene you’ve probably seen countless times in movies and on TV: An eagle flies overhead and emits a rough, piercing scream. It's a classic symbol of wilderness and adventure. The only problem? Bald eagles don't make that sound.

Instead, they emit a sort of high-pitched giggle or a weak scream. These noises are so unimpressive that Hollywood sound editors often dub over bald eagle calls with far more impressive sounds: the piercing, earthy screams of a smaller bird, the red-tailed hawk. If you were a fan of The Colbert Report, you might remember the show's iconic CGI eagle from the opener—it, too, is making that red-tailed hawk cry. Listen for yourself and decide who sounds more impressive.


Two bald eagles guard their prey against two magpies on a snowy field.

Picture a majestic bald eagle swooping low over a lake and catching a fish in its powerful claws. Yes, bald eagles eat a lot of fish—but they don't always catch them themselves. They've perfected the art of stealing fish from other birds such as ospreys, chasing them down until they drop their prey.

Bald eagles will also snack on gulls, ducks, rabbits, crabs, amphibians, and more. They'll scavenge in dumpsters, feed on waste from fish processing plants, and even gorge on carrion (dead, decaying animals).


Two bald eagles perched on a tree.

Trash and carrion aside, they're pretty romantic animals. Bald eagles tend to pair up for life, and they share parenting duties: The male and the female take turns incubating the eggs, and they both feed their young.


Two bald eagles sitting on a rock.

Those romantic partnerships are even more impressive because bald eagles can survive for decades. In 2015, a wild eagle in Henrietta, New York, died at the record age of 38. Considering that these birds pair up at 4 or 5 years of age, that's a lot of Valentine's Days.


Two bald eagles in their large nest.

Bald eagles build enormous nests high in the treetops. The male and female work on the nest together, and this quality time helps them cement their lifelong bond. Their cozy nurseries consist of a framework of sticks lined with softer stuff such as grass and feathers. If the nest serves them well during the breeding season, they'll keep using it year after year. And, like all homeowners, they can't resist the thought of renovating and adding to their abode. Every year, they'll spruce it up with a whopping foot or two of new material.

On average, bald eagle nests are 2-4 feet deep and 4-5 feet wide. But one pair of eagles near St. Petersburg, Florida, earned the Guinness World Record for largest bird’s nest: 20 feet deep and 9.5 feet wide. The nest weighed over two tons.


Two bald eagles in their large nest.

In many animal species, males are (on average) larger than females. Male gorillas, for example, dwarf their female counterparts. But for most birds of prey, it's the opposite. Male bald eagles weigh about 25 percent less than females.

Scientists aren't sure why there's such a size difference. One reason might be the way they divide up their nesting duties. Females take the lead in arranging the nesting material, so being bigger might help them take charge. Also, they spend longer incubating the eggs than males, so their size could intimidate would-be egg thieves.

If you're trying to tell male and female eagles apart, this size difference may help you—especially since both sexes have the same plumage patterns.


A bald eagle flies across the water.

People often get excited about a big soaring bird and yell "It's an eagle!” just before it swoops closer and … oops, it's a vulture. Here's a handy identification tip. Bald eagles usually soar with their wings almost flat. On the other hand, the turkey vulture—another dark, soaring bird—holds its wings up in a shallow V shape called a dihedral. A lot of large hawks also soar with slightly raised wings.


Baby eagle chicks in a nest.

Before European settlers arrived, bald eagles were abundant across the U.S. But with settlement came habitat destruction, and the settlers viewed the eagles as competition for game and as a threat to livestock. So many eagles were killed that in 1940 Congress passed an act to protect the birds.

Unfortunately, another threat rose up at about that time. Starting after World War II, farmers and public health officials used an insecticide called DDT. The chemical worked well to eradicate mosquitos and agricultural pests—but as it traveled up the food chain, it began to heavily affect birds of prey. DDT made eagle eggshells too thin and caused the eggs to break. A 1963 survey found just 471 bald eagle pairs in the lower 48 states.

DDT was banned in the early 1970s, and conservationists began to breed bald eagles in captivity and reintroduce them in places across America. Luckily, this species made a spectacular recovery. Now the lower 48 states boast over 9700 nesting pairs.


An African fish eagle flies over the water.
The African fish eagle is a relative of the North American bald eagle.

You've probably heard of America's other eagle: the golden eagle. This bird lives throughout much of the northern hemisphere. But the bald eagle is only found in North America. It lives across much of Canada and the U.S., as well as northern parts of Mexico.

Though it may be North American, the bald eagle has seven close relatives that are found throughout the world. They all belong to the genus Haliaeetus, which comes—pretty unimaginatively—from the Latin words for "sea" and "eagle." One relative, the African fish eagle, is a powerful symbol in its own right. It represents several countries; for example, it's the national symbol of Zambia, and graces the South Sudanese, Malawian, and Namibian coats of arms.


A bald eagle carries a fish off in its talons.

It seems too weird to be true: While flying, bald eagles sometimes grab each other's feet and spin while plummeting to the earth. Scientists aren't sure why they do this—perhaps it's a courtship ritual or a territorial battle. Usually, the pair will separate before hitting the ground (as seen in this remarkable set of photographs). But sometimes they hold tight and don't let go. These two male bald eagles locked talons and hit the ground with their feet still connected. One subsequently escaped and the other was treated for talon wounds.


Close-up of a bald eagle's face.

What if you could close your eyes and still see? Besides the usual pair of eyelids, bald eagles have a see-through eyelid called a nictitating membrane. They can close this membrane to protect their eyes while their main eyelids remain open. The membrane also helps moisten and clean their eyes.

Eagles also have sharper vision than people, and their field of vision is wider. Plus, they can see ultraviolet light. Both of those things mean the expression "eagle eye" is spot-on.


A bald eagle sits in a snowy tree.

If you're a bald eagle that nests in northern Canada, you'll probably head south for the winter to avoid the punishing cold. Many eagles fly south for the winter and return north for the summer—as do plenty of other bird species (and retired Canadians). But not all bald eagles migrate. Some of them, including individuals in New England and Canada's Maritime provinces, stick around all year. Whether or not a bird migrates depends on how old it is and how much food is available.


A bald eagle

There are several videos online—like the one above—that show a bald eagle swimming in the sea, rowing itself to shore with its huge wings. Eagles have hollow bones and fluffy down, so they can float pretty well. But why swim instead of soar? Sometimes, an eagle will swoop down and grab an especially weighty fish, then paddle it to shore to eat.

Note that the announcer in the video above says that the eagle's talons are "locked" on a fish that's too heavy to carry. In fact, those lockable talons are an urban legend.

New Health-Monitoring Litter Box Could Save You a Trip to the Vet

Unsure if your cat is sick or just acting aloof per usual? A “smart toilet” for your fur baby could help you decide whether a trip to the vet is really necessary.

Enter the Pet Care Monitor: More than a litter box, the receptacle is designed to analyze cat urine for health issues, The Asahi Shimbun in Tokyo reports. Created by the Japan-based Sharp Corporation—better known for consumer electronics such as TVs, mobile phones, and the world's first LCD calculator—the product will be available for purchase on the company’s website starting July 30 (although shipping limitations may apply).

Sensors embedded in the monitor can measure your cat’s weight and urine volume, as well as the frequency and duration of toilet trips. That information is then analyzed by an AI program that compares it to data gleaned from a joint study between Sharp Corp and Tottori University in Japan. If there are any red flags, a report will be sent directly to your smartphone via an application called Cocoro Pet. The monitor could be especially useful for keeping an eye on cats with a history of kidney and urinary tract problems.

If you have several cats, the company offers sensors to identify each pet, allowing separate data sets to be collected and analyzed. (Each smart litter box can record the data of up to three cats.)

The Pet Care Monitor costs about $225, and there’s an additional monthly fee of roughly $3 for the service. Sharp Corporation says it will continue developing health products for pets, and it has already created a leg sensor that can tell if a dog is nervous by measuring its heart and respiratory rates.

[h/t The Asahi Shimbun]


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