Aunque desde la mítica película de Steven Spielberg a los tiburones casi siempre se les percibe como bestias agresivas, la realidad es mucho más compleja. Una investigación realizada por biólogos marinos de la Universidad de Exeter, en el Reino Unido, ha comprobado que estos animales pueden tener personalidades diversas.
Estos científicos han realizado un experimento con tiburones gato en el que han observado una variedad notable en el comportamiento de los individuos de esta especie. En concreto, se ha comprobado que, independientemente del entorno en el que se encuentran, algunos de estos tiburones muestran un comportamiento solitario, mientras que otros son mucho más gregarios y tienden a agruparse en manadas.
El hallazgo, publicado en Behavioral Ecology and Sociobiology, añade una nueva prueba de que los animales no son autómatas que se mueven exclusivamente por mecanismos instintivos, sino que su comportamiento es mucho más complejo y varía entre los individuos de una misma especie.
En nuestro videoblog 'De EL MUNDO al Cosmos', analizamos las implicaciones de este experimento para el estudio del comportamiento animal.
Shark personalities? Repeatability of social network traits in a widely distributed predatory fish
David M. P. Jacoby, Lauren N. Fear, David W. Sims, Darren P. Croft
Interest in animal personalities has generated a burgeoning literature on repeatability in individual traits such as boldness or exploration through time or across different contexts. Yet, repeatability can be influenced by the interactive social strategies of individuals, for example, consistent inter-individual variation in aggression is well documented. Previous work has largely focused on the social aspects of repeatability in animal behaviour by testing individuals in dyadic pairings. Under natural conditions, individuals interact in a heterogeneous polyadic network. However, the extent to which there is repeatability of social traits at this higher order network level remains unknown. Here, we provide the first empirical evidence of consistent and repeatable animal social networks. Using a model species of shark, a taxonomic group in which repeatability in behaviour has yet to be described, we repeatedly quantified the social networks of ten independent shark groups across different habitats, testing repeatability in individual network position under changing environments. To understand better the mechanisms behind repeatable social behaviour, we also explored the coupling between individual preferences for specific group sizes and social network position. We quantify repeatability in sharks by demonstrating that despite changes in aggregation measured at the group level, the social network position of individuals is consistent across treatments. Group size preferences were found to influence the social network position of individuals in small groups but less so for larger groups suggesting network structure, and thus, repeatability was driven by social preference over aggregation tendency.
Humans have a variety of personality traits. And now, a new study says sharks have personalities as well. Yes, sharks.
Researchers at the Marine Biological Association of the UK and the University of Exeter studied ten small groups of cat sharks in three different habitats, and looked at their behavioral patterns.
The research shows that even though sharks are depicted as mindless, eating machines they have unique social patterns that determine how they interact with other sharks.
One of the researchers explained in a press release: "These results were driven by different social preferences ... that appeared to reflect different strategies for staying safe. Well-connected individuals formed conspicuous groups, while less social individuals tended to camouflage alone."
These social or antisocial personality traits were likely developed by the young sharks to avoid being another animal's lunch.
BBC notes this is far from the first piece of research to suggest that animals have personalities. There has been a lot of evidence that shows individual behavior differences in a large number of species.
And these findings for the catshark actually line up with some results from completely separate research on the lemon shark. Those findings showed consistent personality traits in their test subjects as well.
So do you think Jaws hung out with other sharks or was more of a loner when he wasn't terrorizing fisherman?
This video includes images from Joachim S. Muller / CC BY NC SA 2.0, Emoke Denes and Anthony Patterson
A small spotted catshark (David Sims/University of Exeter)
Although personalities are known to exist in many animals, they are usually defined by characteristics such as how exploratory, bold or aggressive an individual is.
This research, led by the University of Exeter and the Marine Biological Association of the UK (MBA), found that individual sharks have their own personality traits.
The small-spotted catshark or lesser spotted dogfish, Scyliorhinus canicula, is a catshark of the family Scyliorhinidae. It is found on the continental shelves and the uppermost slopes off the coasts of Norway and the British Isles south to Senegal, including the Mediterranean between latitudes 63° N and 12° N
Study shows sharks have personalities
Some sharks are ‘gregarious’ and have strong social connections, whilst others are more solitary and prefer to remain inconspicuous, according to a new study which is the first to show that the notorious predators have personality traits.
Personalities are known to exist in many animals, but are usually defined by individual characteristics such as how exploratory, bold or aggressive an individual is.
Research led by the University of Exeter and the Marine Biological Association of the UK (MBA) has shown for the first time that individual sharks actually possess social personalities, which determine how they might interact with group mates in the wild.
In a study published today in the journal Behavioral Ecology and Sociobiology, the team tested for social personality by recording the social interactions of groups of juvenile small spotted catsharks in captivity under three different habitat types.
The species of shark (Scyliorhinus canicula), found throughout the northeast Atlantic and Mediterranean, group together by resting around and on top of one another, sat on the bottom of the seafloor.
Working at the MBA in Plymouth, Devon, ten groups of sharks were monitored in large tanks containing three habitats which differed in their level of structural complexity.
Dr David Jacoby, a behavioural ecologist now at the Institute of Zoology, London said: “We found that even though the sizes of the groups forming changed, socially well-connected individuals remained well-connected under each new habitat. In other words, their social network positions were repeated through time and across different habitats.
“These results were driven by different social preferences (i.e social/antisocial individuals) that appeared to reflect different strategies for staying safe. Well-connected individuals formed conspicuous groups, while less social individuals tended to camouflage alone, matching their skin colour with the colour of the gravel substrate in the bottom of the tank.”
Professor Darren Croft, of the Centre for Research into Animal Behaviour in Psychology at the University of Exeter, added: “We define personality as a repeatable behaviour across time and contexts. What is interesting is that these behaviours differ consistently among individuals. This study shows, for the first time, that individual sharks possess social personalities.”
He added: “In the wild these small juveniles can make easy prey items for larger fish, so different anti-predator strategies are likely to have evolved. More research, however, is required to truly test the influence of predators on social personality traits in sharks. This study is the first step in that direction.”
‘Shark personalities? Repeatability of social network traits in a widely distributed predatory fish’ by David Jacoby, Lauren Fear, David Sims and Darren Croft is published today in the journal Behavioral Ecology and Sociobiology.
The work was funded by the Fisheries Society of the British Isles.
Date: 2 October 2014
La pintarroja, pintarrosa o pintada de Cantabria (Scyliorhinus canicula) es una especie de elasmobranquio carcarriniforme de la familia Scyliorhinidae.2 Es un tiburón gato muy común en las costas cantábricas.
De color gris amarillento con pequeñas manchas pardas, negras y, en ocasiones, blancas más pequeñas que en el alitán. Es de hábitos nocturnos, reposa sobre fondos arenosos hasta los 400 m de profundidad y se alimenta de crustáceos, moluscos y cefalópodos marinos.