Breathe and Eat

Most life forms need oxygen to survive—and not just a little now and then. The supply must often be constant, because oxygen is what enables an organism’s cells to make energy. While humans take an average of 20 breaths per minute, many other animals have evolved amazing ways to get the oxygen they need, or limit how much they use.

But nothing survives on air alone. All organisms need sugars, fats, and protein to survive. These nutrients, plus necessary vitamins and minerals, provide the energy needed to grow, move and reproduce. Most plants convert energy from the Sun to make their own nutrients, while animals obtain nourishment by eating plants and other living things. While the need for food is basic, the array of tools and strategies for finding a meal is astounding.

Take a Breath and Hold It

The southern elephant seal spends about two months a year on land in Antarctica and the other 10 mostly underwater, hunting fishes and squids in the frigid Southern Ocean. While there, the seal can dive nearly a mile beneath the surface of the ocean. Greatly slowing down their heart rate, combined with a huge volume of blood that has a high concentration of hemoglobin, the molecule that carries oxygen, lets these seals stay underwater for up to two hours without surfacing for air. 

Consummate divers, elephant seals only stay on seashores for a couple months every year. NOAA

Consummate divers, elephant seals only stay on seashores for a couple months every year.

NOAA


 

Getting By On Less Oxygen

When a bear settles into its winter den and enters hibernation, its oxygen intake plummets. The bear may only inhale once a minute, its heart slows dramatically, and blood flow to vital organs dwindles to 10 percent of normal. While bears are the most familiar hibernators, many creatures, including birds, amphibians, and invertebrates have evolved similar specializations that reduce oxygen use.

Brown bears like this one spend up to half of the year in hibernating to conserve energy.  Wikimedia/Marshmallow 

Brown bears like this one spend up to half of the year in hibernating to conserve energy. 

Wikimedia/Marshmallow 


Stealing a Meal 

Parasite comes from the Greek word parasitos, meaning someone who eats at another’s table. In nature, parasites are unwelcome dinner guests: Rather than making or gathering their own food, they let other organisms do the work and then steal nutrients from their hosts, drinking blood or even feeding directly from their cells. The parasitic corpse flower, for instance, has no stem, leaves or roots. Instead of using energy from the Sun to make nutrients, the corpse flower draws all of its nourishment from its host, a species of vine in the grape family. 

A corpse flower in bloom in Malaysia.  Wikimedia/Raphaelhui 

A corpse flower in bloom in Malaysia. 

Wikimedia/Raphaelhui 


 

Big Bites

At 700 meters or more below the surface of the ocean, the lack of sunlight means food can be hard to come by. Some animals address the problem by eating extra-big meals that they swallow whole to make sure they don’t miss even a piece of their prey. One species, the black swallower, can gulp down a fish 10 times its own weight and up to four times its length. Two rows of large, pointed teeth on each jaw can collapse to make room as prey ratchets down the gullet, to be slowly digested in a stomach with expandable walls.

The stomach of the Black Swallower expands to hold prey much larger than the fish itself. ©AMNH/R.Mickens 

The stomach of the Black Swallower expands to hold prey much larger than the fish itself.

©AMNH/R.Mickens 


Stealing a meal and swallowing it whole are just two ways to grab a bite to eat—stop by Life at the Limits to find more extraordinary examples, and get a whiff of the corpse flower’s distinctive rotten scent.