When Animals Help Each Other
Cooperation within and between different animal species has its advantages for all parties involved.
A recent study published in the journal Marine Mammal Science investigated an interesting premise: the possibility that humpback whales display altruism, given the many stories of the giant creatures seeming to "help" other species such as seals. This 2009 account in Natural History Magazine is a good example of the phenomenon (in the photo above, a killer whale can be seen at center, next to a seal on an ice floe while a humpback whale looms in the foreground. Credit: J. Durban).
That story spawned the new study, which examined more than 100 humpback whale and orca interactions from various published and anecdotal accounts. When all was said and done, the researchers noted multiple instances of humpback whales rushing to the scene of attacks by the killer whales on animals of a species other than their own.
The researchers said that while it made sense for humpbacks to defend their own calves, they had nothing to gain by meddling in attacks on other species. Were they displaying altruism? "Although reciprocity or kin selection might explain communal defense of conspecific calves, there was no apparent benefit to humpbacks continuing to interfere when other species were being attacked. Interspecific altruism, even if unintentional," the scientists wrote, "could not be ruled out."
Is it surprising that animals might practice a bit of altruism? Maybe it shouldn't be. In fact the animal world is full of species you might not expect to be quite so selfless. Read on for more.
Rats aren't exactly known for their social graces. Certainly where there is one rat, there are bound to be many more, and rats in a large-enough group can create swarms at cause plagues.
Humans typically associate rats with selfish behavior, however. Consider the idiomatic expressions related to rodents. "To rat" on someone means to speak out against an individual's bad behavior to enhance one's own reputation. "A rat race" refers to a fiercely competitive struggle.
Rats do exhibit selfless behavior, find researchers at Champalimaud Centre for the Unknown, in Lisbon, Portugal. Experimenters placed rats into pairs and provided one of the rats a choice: open one door and get a food morsel for yourself; open another and both rats receive a reward. Out of 15 rats tested, all but one made unselfish choices consistently.
The rats in fact selected the prosocial outcome around 70 percent of the time. These findings are in line with previous studies that show rats seem to have each other's back. They will attempt to free a trapped comrade and exhibit pain and anxiety responses at the sight of another rat in distress.
Red squirrels may be furry and cute, but they're typically solitary and territorial animals. Red squirrels set out on their own between nine and 11 weeks of age. From then on, the only interactions they have with other squirrels are when squirrels pair up to mate and care for their young. Despite their isolation from one another, scientists who published a 2010 study in the journal Nature Communications found that red squirrels will adopt their relatives
if the mother dies while caring for her young. Squirrel adoption is an exceedingly rare event, however; the researchers only observed five cases out among more than 2,000 litters over two-decade-long period.
Dogs famously are referred to as man's best friend, but there are other species as well with whom dogs have established friendships. Like red squirrels, dogs will take in orphans in need of a parent's care and attention. Unlike red squirrels, dogs don't necessarily care whether the animal is a family member or even a member of the same species. Dogs have been documented adopting kittens, baby foxes, tiger cubs, fawns, ducklings, lambs and more. This behavior is selflessly altruistic, as the dog couldn't expect any benefit from caring for a member of another species.
Dolphins are animals that may as well swim in a conga line because they always seem to have each other's backs... or dorsal fins as the case may be.
The American Naturalist published a study in 1982 documenting the ways researchers observed dolphins supporting other members of their pod. If one dolphin were injured, another might stay behind to act as a guardian, potentially exposing itself to predators. If a dolphin were enfeebled and couldn't easily surface for air, another might swim underneath and provide a nudge for the assist.
Dolphins have come to the aid of one another, but also other species, including humans. There have been numerous stories of pods of dolphins rescuing humans from sharks, such as surfer Todd Endris who survived an encounter with a great white in 2007 or long-distance swimmer Adam Walker, who was stalked by a shark on a swim to raise money for whale and dolphin conservation in 2014.
Are all primates as charitable as humans? Looking at the evidence regarding chimpanzees suggests one of our closest human relatives can be altruistic as well. Although some previous studies had concluded chimps were indifferent to the welfare of their own kind, research published in the Proceedings of the National Academy of Sciences in 2011 shows that these primates engaged in empathy-based altruism, based on an experiment similar in design to the one conducted on the rats, with a food reward either going to one animal or a pair depending on the choice of the subject. Another study conducted in 2007 at Ngamba Island Chimpanzee Sanctuary in Uganda found that chimps were even willing to help humans without the immediate possibility of reward. Chimps in the wild have also shown similar cooperative behavior, with relative regularly sharing food and adopting orphans within the group whose parents had died.
Fish travel in schools, so it makes sense that they cooperate with one another. But some species will work with others in order to achieve a mutually beneficial outcome. Grouper will partner will eel and wrasse during a hunt, while coral trout will join up with octopuses in order to catch their prey, as described in the journal Nature Communications in 2013. Both the grouper and the coral trout use a rudimentary form of "sign language" to signal prey to their hunting party.
The raven was anything but accommodating to the narrator of Edgar Allen's most famous poem. Aside from their black feathers, ravens are also known for their intelligence. But like a human with too much intelligence and not enough sense, are these birds so clever they don't feel the need to be charitable? Apparently not, observed two scientists who spent three years observing these birds in the forests of Maine during the 1990s. When a hungry raven stumbled unto a major kill, rather than immediately gorging itself, as any animal solely interested in its own survival would be expected to do, the raven lets out the equivalent of a yell to alert other birds in the area of the available meal. The call signals not only relatives but other ravens who are completely unknown to the food finder. The behavior serves a purpose, however. Ravens belong in one of two groups, according to the researchers: residents and wanderers. Residents have backup in case their find food, but wanderers don't. In sounding the food bell for the whole neighborhood to hear, a wanderer can attract a big enough crowd, particularly other young wanderers, that it won't be displaced by residents who might otherwise claim a kill for themselves.
Vampire bats aren't cuddly creatures. Anything with a reputation for consuming the blood of its prey won't win many friends. But vampire bats do look out for their own. Given that vampire bats have a fast metabolism and will die if they don't feed every day or two, one might expect that it was every bat for itself come meal time. However, bats will share their food supply not only with juveniles but also adults who weren't fortunate enough to find their own grub, found a Nature study published in 1984. A successful hunter will regurgitate enough blood into a hungry bat's mouth to allow the roostmate to live another day. The gift of a meal one night could be reciprocated the next, so it pays for bats to answer the door, metaphorically-speaking, when its neighbor comes knocking for a spot of blood.
Given that a single colony can include up to tens of millions of members, ants certainly possess teamwork skills. This trait can be credited for giving ants a foothold on every continent except Antarctica. Colony unity depends on individual ants working to fulfill their respective roles. Sterile worker ants, for example, will care for the offspring of the queen of a colony. Some ants go even further, however, giving up their lives for the sake of the colony. When they fall ill or are near death, worker ants of the species Temnothorax unifasciatus will leave the colony and spend the last of their energy getting as far away as possible in order to prevent illness from spreading, found a study published in 2010 in the journal Current Biology.
Other ants, such as the nine Bruneian Camponotus species studied for an article published in the Journal of Chemical Ecology, explode in a poisonous spray if they are in a losing fight with a potential threat to the colony.
Similar to ants, honeybees operate as a kind of superorganism with a well-defined hierarchy. The queen is on top, and the worker bees and drones spend their lives supporting the colony, toiling within an age-based system determining division of labor. Given that the queen is the lynchpin for the entire colony, it's fair to assume her absence would lead to anarchy.
A study published in the journal Current Biology/url], however, found that honeybees can function even in the absence of the queen through which they are all related. In the absence of a queen bee, a number of workers will split their time between reproduction, an arguably selfish but metabolically challenging task, and foraging and defense duties, prosocial but risky. The specialists become generalists to try to keep the colony buzzing. Unfortunately, unless the colony was in the midst of raising a new queen before the old one died, a queenless colony is a doomed enterprise, as workers can only produce male drones. Once all of the worker bees are gone, the colony collapses.