"Long before it's in the papers"
April 29, 2009

RETURN TO THE WORLD SCIENCE HOME PAGE

Dolphins and the evolution of teaching

“Pointing” motions, oddly repetitious behavior seen as possible attempts to pass on knowledge to young

Aug. 7, 2008
World Science staff

With flu­id, some­times playful-looking move­ments, a moth­er dol­phin leads her calf to the seafloor and starts pok­ing around for a meal—fish hid­ing in the sand. The young­ster seems to watch close­ly.

The scene, cap­tured on vid­e­o, is one of many cases filmed by re­search­ers of what they de­scribe as dol­phins ap­par­ently teach­ing their young.

At­lan­tic spot­ted dol­phins (Ste­nel­la fron­t­a­lis) ap­par­ent­ly teach their calves for­ag­ing skills, re­search­ers say. A vi­deo (MPEG for­mat) shows ac­tiv­i­ty that sci­en­tists be­lieve may rep­re­sent teach­ing be­hav­ior. (Im­age cour­te­sy NOAA)
While a few an­i­mal spe­cies have been re­ported to “teach” their young sur­viv­al skills, dol­phins seem to dis­play some teach­ing in­nova­t­ions shown by none oth­ers ex­cept hu­mans, sci­en­tists say in a new stu­dy.

Re­search­ers are fas­ci­nated by re­ports of an­i­mal teach­ing be­cause it may re­veal an abil­ity thought to be pos­sibly un­ique to hu­mans—the ca­pacity to in­fer some­one else’s thoughts. This abil­ity, a mile­stone in ev­o­lu­tion, is some­times called “the­ory of mind.”

An­oth­er crea­ture de­scribed as hav­ing im­pres­sive teach­ing strate­gies is the meer­kat, a type of mon­goose. One study not­ed that meer­kats give their young in­jured prey, such as stinger-deprived scor­pi­ons, so the pup can fin­ish the kill and en­joy the meal. The adult looks on, pro­vid­ing more aid if nec­es­sary. As pups grow, adults grad­u­ally hike the dif­fi­cul­ty lev­el by of­fer­ing harder-to-handle prey.

Dol­phin “teach­ing” ap­pears to in­volve some dif­fer­ent tricks, ac­cord­ing to the new stu­dy. These in­clude an ap­par­ent com­mu­nica­t­ion com­po­nent: the ocean mam­mals make “point­ing” mo­tions with their snout, ac­tions pre­vi­ously do­cu­mented in cap­ti­vity but not in the wild. 

The find­ings add to pre­vi­ous re­search sug­gest­ing dol­phins have a “the­ory of mind,” ac­cord­ing to the in­ves­ti­ga­tors, but they added that more ev­i­dence may be needed.

Re­gard­less, the study shows teach­ing may be a key to how dol­phin “so­cial learn­ing and pos­sibly cul­ture are trans­mit­ted from one genera­t­ion to the nex­t,” wrote the re­search­ers, Court­ney Bend­er of Flor­i­da At­lantic Uni­ver­s­ity and col­leagues, in the stu­dy. The re­port ap­pears in the July 29 on­line is­sue of the re­search jour­nal An­i­mal Cog­ni­tion.

Bend­er and col­la­bo­ra­tors an­a­lyzed ar­chives of vid­e­os tak­en of At­lan­tic spot­ted dol­phins be­tween 1991 and 2004 from the ar­chives the Wild Dol­phin Proj­ect, a re­search group based in Ju­pi­ter, Fla. They com­pared the for­ag­ing ac­ti­vi­ties of moth­ers when they were in and out of the pres­ence of their own calves. The idea was that moth­ers might change their for­ag­ing styles in par­tic­u­lar ways to make a “teach­ing” ex­pe­ri­ence of it.

An­a­lyz­ing 38 episodes of for­ag­ing, each last­ing from an in­i­tial search to a cap­ture and eat­ing of prey, the team re­ported sig­nif­i­cant dif­fer­ences in the episodes with calf pre­s­ent. The most strik­ing change: when the calf was there, moth­ers stretched out the chase eight times long­er on av­er­age, re­peat­edly cap­tur­ing, let­ting go and re-cap­tur­ing the same vic­tim—as if to dem­on­strate the tech­nique. 

“These ex­ag­ger­at­ed for­ag­ing be­hav­iors may pro­vide a win­dow of op­por­tun­ity for the calves to ob­serve, and pos­sibly learn from, the ex­am­ple,” Bend­er and col­leagues wrote.

But the point­ing-like ges­tures seen dur­ing the for­ag­ing with calves were “par­tic­u­larly in­ter­est­ing,” they added. These con­sisted of “ex­ag­ger­at­ed move­ments in the di­rec­tion of the prey,” ori­ent­ing the body in its di­rec­tion, as if to point it out. This “may be an attention-directed ref­er­en­tial be­hav­ior si­m­i­lar to the spon­ta­ne­ous point­ing ob­served by dol­phins dur­ing ex­pe­ri­ments in cap­ti­vity,” Bend­er’s group wrote.

To con­firm wheth­er the ob­served be­hav­ior is really teach­ing, re­search­ers are cur­rently an­a­lyz­ing wheth­er the calfs are really learn­ing from it, the sci­en­tists added. But even with­out that da­ta, they wrote, “we be­lieve that this study de­tail­ing the al­tered for­ag­ing be­hav­ior of the moth­ers is a sig­nif­i­cant find­ing in the ar­ea of an­i­mal cog­ni­tion.”

* * *

Send us a comment on this story, or send it to a friend

 

Sign up for
e-newsletter
   
 
subscribe
 cancel

On Home Page         

LATEST

  • Discov­ery of “furth­est ob­ject” said to pave way for prob­ing early cos­mos

  • A w­arm T­V may drive away feel­ings of loneli­ness, re­jection

EXCLUSIVES

  • Re­port: cells “from space” have un­usual make­up

  • Dol­phins and the evo­lution of teach­ing

  • D­rug may tri­ck body into “think­ing” you ex­ercised

  • Tit-for-tat: bi­rds found to re­pay war­­time help

  • Musi­cal genes may be com­ing to light

MORE NEWS

  • R­ock-hurl­ing zoo chimp stock­ed am­mo in ad­vance: study

  • Fai­th found to re­duce er­rors on psycho­logical test

  • Dood­ling gets its due: ti­ny art­works may aid mem­ory

  • From or­al to mor­al? Dirty deeds may prompt “bad taste” reac­tion

With fluid, sometimes playful-looking movements, a mother dolphin leads her calf to the seafloor and starts poking around for a meal—the fish hiding in the sand. The youngster seems to watch closely. The scene, captured on video, is one of many cases filmed by researchers of what they describe as dolphins apparently teaching their young. While a few animal species have been reported to “teach” their young survival skills, dolphins seem to display some teaching innovations shown by none others except humans, scientists say in a new study. Researchers are interested in animal teaching because it appears to reveal a cognitive ability thought to be possibly unique to humans—the capacity to infer someone else’s thoughts. This ability, a milestone in animal evolution, is sometimes called “theory of mind.” Another creature described as having impressive teaching strategies is the meerkat, a type of moongoose. One study noted that meerkats give their young injured prey, such as stinger-deprived scorpions, so the pup can finish the kill and enjoy the meal. The adult looks on, providing more aid if necessary. As pups grow, adults gradually hike the difficulty level by offering harder-to-handle prey. Dolphin “teaching” appears to involve some different tricks, according to the new study. These include an apparent communication component: the ocean mammals make “pointing” motions with their snout, activities previously recorded in captivity but not in the wild. The findings add to previous research suggesting dolphins may have a “theory of mind,” according to the investigators, but they added that more evidence may be needed. Regardless, the study shows teaching may be a key to how dolphin “social learning and possibly culture are transmitted from one generation to the next,” wrote the researchers, Courtney Bender of Florida Atlantic University and colleagues, in the study. The report appears in the July 29 online issue of the research journal Animal Cognition. Bender and collaborators analyzed archives of videos taken of Atlantic spotted dolphins between 1991 and 2004 from the archives the Wild Dolphin Project, a research group based in Jupiter, Fla. They compared the foraging activities of mothers when they were in and out of the presence of their own calves. The idea was that mothers might change their foraging styles in particular ways to make a “teaching” experience of it. Analyzing 38 episodes of foraging, each lasting from an initial search to a capture and eating of prey, the team reported significant differences in the episodes with calf present. The most striking change: when the calf was there, mothers stretched out the chase eight times longer on average, repeatedly capturing, letting go and re-capturing the same victim—as if to demonstrate the technique. “These exaggerated foraging behaviors may provide a window of opportunity for the calves to observe, and possibly learn from, the example,” Bender and colleagues wrote. But the pointing-like gestures seen during the foraging with calves were “particularly interesting,” they added. These consisted of “exaggerated movements in the direction of the prey,” orienting the body in its direction, as if to point it out. This “may be an attention-directed referential behavior similar to the spontaneous pointing observed by dolphins during experiments in captivity,” Bender’s group wrote. To confirm whether the observed behavior is really teaching, researchers are currently analyzing whether the calfs are really learning from it, the scientists added. But even without that data, they wrote, “we believe that this study detailing the altered foraging behavior of the mothers is a significant finding in the area of animal cognition.”