Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Speaker 1: Lauren Volabon. Here. It's early April as I record this episode,
Speaker 1: and spring is springing. My neighborhood's lawns are growing again,
Speaker 1: which means we're getting close to the long, warm season
Speaker 1: of one of my favorite scents, freshly cut grass. The
Speaker 1: scent is amazing, sweet, bright green, but those clippings would
Speaker 1: not be delicious on top of a salad or in
Speaker 1: the middle of a blt. A grass is both leafy
Speaker 1: and green, like spinach and lettuce, but assuming that you're
Speaker 1: a human, it is not good for you to eat.
Speaker 1: Generally speaking, you can eat grass. It's natural and not
Speaker 1: toxic unless it's been sprayed with pesticides. You just can't
Speaker 1: digest it. A grass has zero of the nutritional value
Speaker 1: for humans that it does for cows, yacks, deer, sheep,
Speaker 1: and other ruminants. Ruminants are mammals that have special digestive systems,
Speaker 1: including a four chambered stomach, that allow them to get
Speaker 1: at the nutrients in grass. But okay, let's back up
Speaker 1: a little. What is grass. Grasses are a family of
Speaker 1: plants that occur on every continent, yes, even Antarctica. There
Speaker 1: are over eleven five hundred species in over seven hundred
Speaker 1: and fifty genera. It's one of the largest families of
Speaker 1: plants on Earth. The family does include lots of plants
Speaker 1: that we humans have domesticated and specialized to use as food.
Speaker 1: Grains like wheat, oats, rice, and corn are all the
Speaker 1: seeds of different grasses. Sugar cane is a tall, sturdy
Speaker 1: category of grass that we press to obtain sweet juice
Speaker 1: that we then process into sugar, molasses, and rum, but
Speaker 1: usually we don't eat the leafy part of the grass itself.
Speaker 1: One exception is young and tender bamboo shoots, though even
Speaker 1: those have to be boiled first. We generally don't eat
Speaker 1: the grass part of grasses because we don't have the
Speaker 1: stomachs for it or the teeth. Leaves of grass contain
Speaker 1: a lot of silica, which is a tough mineral deposit
Speaker 1: that helps give them structural support. A research has shown
Speaker 1: that it also makes grasses more difficult for insect and
Speaker 1: mammalian herbivores to chew and digest. If we tried to
Speaker 1: eat grass over time, it would wear away the enamel
Speaker 1: on our teeth and we only get the one set
Speaker 1: as adults. Ruminants, however, have teeth that are constantly growing,
Speaker 1: so as their teeth wear down, they grow back up again.
Speaker 1: Ruminants also tend to chew in a side to side motion,
Speaker 1: not up and down like we do. This helps shred
Speaker 1: tough grass into tiny bits, making it easier to digest
Speaker 1: when it gets to the stomach. Unlike humans, ruminants, like cattle,
Speaker 1: don't have a single past their food before it enters
Speaker 1: their digestive tract. They chew their cud. After swallowing a
Speaker 1: mouthful of grass, it enters a cow's reticulum, which is
Speaker 1: the first chamber in their four chambered stomach. The muscular
Speaker 1: reticulum can push the grass back into the cow's mouth
Speaker 1: for extra chewing. Pieces of grass can pass easily from
Speaker 1: the reticulum into the second chamber, called the rumen after
Speaker 1: which ruminants are named. This is the largest compartment of
Speaker 1: the stomach. In fully grown cattle, it can be the
Speaker 1: size of a fifty five gallon drum that's over two
Speaker 1: hundred liters in the roomin lots of friendly bacteria help
Speaker 1: break down tough parts of plants by eating away at
Speaker 1: them and releasing nutrients that the cow's body can absorb.
Speaker 1: A similar thing happens in human intestines with human safe foods.
Speaker 1: The trick is that the cow's complex stomach keeps the
Speaker 1: grass they are long enough for the process of rechewing
Speaker 1: and the bacteria to really do the work and breaking
Speaker 1: everything down and getting more out of the grass than
Speaker 1: you or I could. There was a period in history
Speaker 1: where a distant and hairer cousin of humans might have
Speaker 1: been able to digest grass around three and a half
Speaker 1: million years ago. But if a human ate grass today,
Speaker 1: it might cause stomach upset, vomiting, or diarrhea as our
Speaker 1: body attempted to deal with this, not food, or at
Speaker 1: best it might just pass through undigested. But okay, the
Speaker 1: digestive systems of dogs and cats are more like humans
Speaker 1: than they are like ruminants, So if they can't digest it,
Speaker 1: why do dogs and cats eat grass? The scientific answer
Speaker 1: is that no one is sure. The common conception is
Speaker 1: that dogs and cats do this because they're ill and
Speaker 1: trying to make themselves vomit, or because they're missing something
Speaker 1: in their diets, but research doesn't back that up. In
Speaker 1: two thousand and eight, scientists the University of California Davis
Speaker 1: tried to cut through the weeds and shed some light
Speaker 1: on this mystery. They sent out surveys to twenty five
Speaker 1: dog owning veterinary students. All reported that their canines ate grass.
Speaker 1: A nun said that they observed any signs of illness
Speaker 1: before their dogs chowed down, and only eight percent so
Speaker 1: that their dogs vomited afterwards. The researchers also surveyed forty
Speaker 1: seven dog owners who took their pets to the university's
Speaker 1: teaching hospital for outpatient care. Seventy nine percent that they
Speaker 1: saw their pets eating plants, mostly grass. Four dogs were
Speaker 1: ill beforehand, and only six vomited afterward. The team then
Speaker 1: opened the survey up to three thousand people who answered
Speaker 1: a series of online questions, yielding useful data from about
Speaker 1: one thousand, six hundred people. Of those, sixty eight percent
Speaker 1: saw their dogs eating plants mostly grass on a daily
Speaker 1: or weekly basis. Only eight percent showed signs of sickness beforehand,
Speaker 1: and some twenty two percent vomited afterwards. In the same study,
Speaker 1: the researchers found that grass eating is also common in
Speaker 1: cats and also has nothing to do with upset stomachs
Speaker 1: or other illnesses. Most cats, like dogs, do not vomit afterward.
Speaker 1: They found that it's a common behavior in normal cats
Speaker 1: and dogs, regardless of diet, and they specified that the
Speaker 1: behavior of vomiting seems to be incidental to grass eating.
Speaker 1: So maybe dogs and cats just like the taste or
Speaker 1: texture of grass, or maybe it's just there and borum
Speaker 1: snacking can strike us all. Today's episode is based on
Speaker 1: the articles why do dogs and cats eat grass? And
Speaker 1: Many animals eat grass, so why don't humans? On how
Speaker 1: Stuffworks dot Com, both written by John Partano. Brain Stuff
Speaker 1: is production by Heart Radio in partnership with how Stuffworks
Speaker 1: dot Com and is produced by Tyler Klang. Four more
Speaker 1: podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts,
Speaker 1: or wherever you listen to your favorite shows.