Things that eat what you wouldn't expect: Carnivores that eat plants

Carnivores That Eat Plants

 

We all know that some animals, such as pigs and bears, are omnivores. But there are also some animal species belonging to groups we think of as carnivorous that subsist partially, or even entirely, on plants.

 

One example of this is the maned wolf. It's a type of canine that lives in South America. While canines are generally thought of as carnivorous, the maned wolf is an omnivore. In fact, according to some studies, more than 50% of its diet is plant matter. This includes sugar cane, tubers, and fruit. In fact, one type of fruit is so heavily eaten by the maned wolf that it's colloquially known as the "wolf apple". Meat-heavy diets are actually bad for the maned wolf, since they develop bladder stones if they don't get enough plant matter to eat.

 

Just about everybody knows that the giant panda subsists almost entirely on bamboo. Most people are also aware that most bears eat at least some plants. The polar bear is the main exception, and even that is believed to have more to do with lack of availability than anything. But one type of true bear was known for an almost entirely herbivorous diet. This was the cave bear. Some scientists believe that it may have eaten meat if given the opportunity, but all the evidence says that it was primarily an herbivore.

 

Aardvarks have evolved a mutually beneficial relationship with a type of plant called the aardvark cucumber. The aardvark eats the fruit of the plant for water, then defecates the seeds and buries them. This symbiotic relationship is interesting because the aardvark is otherwise an exclusive insectivore. As a matter of fact, carnivores can actually be preferred seed dispensers to herbivores, since they can't chew up or fully digest the seeds. Many scientists believe that avocados evolved their fatty flesh and durians their intense odor to trick carnivores into eating them.

 

But these herbivorous tendencies in carnivores aren't just confined to mammals. They have been observed in other chordate classes, in places that might be very surprising.

 

Crocodilians are considered quintessentially carnivorous, and alligators are no exception. But some individual alligators have been known to eat fruit on occasion. No one is quite sure why, and the alligators still mostly eat meat, but some scientists believe it may be an adaptation for when food supplies are low. Some captive alligators like fruit so much that their keepers regularly give them watermelon in addition to the more expected diet of meat. And believe it or not, some prehistoric crocodilians were full-on herbivores.

 

Sharks are known for their tendencies to eat just about anything, even things generally not considered food. One tiger shark was caught with half a suit of armor in its stomach. So it may not be too surprising to find the occasional shark with plant matter in its gullet. But one type of shark, the bonnethead, regularly eats seagrass. In fact, it actually constitutes more than half its diet in some cases. The bonnethead is the only shark known to regularly eat plants.

 

If there's one type of animal nobody would expect to eat plants, it's the spider. But even it has an herbivorous species. Bagheera kiplingli is a species of jumping spider that lives in Central America, and holds the claim to fame of being the only spider that's almost wholly herbivorous. How does it accomplish this? It feeds on protein-rich pods growing certain types of tree, which said trees develop as part of a symbiotic relationship with certain species of ant.

 

"Herbivorous carnivores" aren't even confined to the animal kingdom. Perhaps the strangest example of a carnivore that eats plants is Nepenthes ampullaria. This is a type of pitcher plant that has evolved an exclusively herbivorous diet. That's right: a carnivorous plant that has turned to eating plant matter. Hailing from parts of Southeast Asia and Oceania, this is a pitcher plant that collects leaves and other plant debris that fall from trees, which it then digests. One would never expect a type of plant that evolved to catch animals to become a herbivorous detritivore, but truth is stranger than fiction.

 

Of course, these aren't the only cases of animals that eat things you wouldn't expect. I'll be back with a follow-up.