Deadly Alliances: Male Dolphins engage in sexually coercive mating behaviour…in gangs!

Hi everyone!

Today I’m going to talk about the Common Bottlenose Dolphin, Tursiops truncates. They belong to the family of Delphinidae and their Genus name is Tursiops.

Legend has it that dolphins in Greek mythology are messengers of Poisedon. They swim and frolick with mermaids and have guided ships to safety. (Bioexpediton, 2012) To us, they are happy and playful sea creatures. However, dolphins too, have an aggressive nature. Thus, to understand their behaviour, we focus on the area of Group dyanamics and Social interactions between the Common Bottlenose dolphin.

Basic facts on social groups in the Common Bottlenose dolphins

•  The group name of the common bottlenose dolphins is called a pod. (National Geographic Society, 2013 )
•  Bottlenose dolphins typically live in groups that range in size from a few individuals to over 100. (Hogan, 2012)
• Usually, common types of aggression displayed by the Common Bottlenose dolphins  during interactions include:
• Tail slaps
• Biting
• Ramming
• (Hogan, 2012)

 View how the aggression is played out below!

Secrets of Dolphin’s Aggression

[youtube=http://www.youtube.com/watch?v=BBUBGMgI2oU]

A New Type of Aggressive behaviour

However, biologists have discovered a new form of aggressive behaviour in the area of reproduction and mating.  That is- Male Common Bottlenose dolphins actually form alliances with one another and travel around in gangs, holding female dolphins captive for sexual reproduction!  Usually, there are 2-3 male dolphins  and they will kidnap a female dolphin, taking turns to guard her to ensure  higher chances of mating. What’s more astonishing is that this herding behavior is “highly organized.” (Discovery Communications Inc, 2013) Read the full story here. 

Reason for herding behaviour

A theory proposed by researchers said that “Herding by male gangs is a strategy to prevent females from reproducing with rival dolphins. In this way, a male alliance may increase the chances that the group’s members will breed the next generation of dolphins.” (Discovery Communications Inc, 2013)

Significance of these close knit alliances

The amazing discovery made is that “the males of a species form stable long-term bonds with one another. In some cases, those bonds last more than 10 years.” (Discovery Communications Inc, 2013) Therefore, “Male dolphins would form not only primary but also secondary social bonds—bonds extending beyond an original group to encompass new individuals—to fight rival males and stalk potential mates.” (Discovery Communications Inc, 2013)

Watch the video below to see the amazing alliance formed by 14 Male Common Bottlenose dolphins in their bid to find a mate.

Bottlenose Dolphin Gang Rumble

[youtube=http://www.youtube.com/watch?v=ji9FHnNraI8]

We see a similar behavior in baboons, however close bonds are only between female baboons  to increase their lifespan. Read the article pdf here!

Hoped you enjoyed this interesting read! x

References:

“Bottlenose Dophin” , by National Geographic Society.com, 2013. URL: http://animals.nationalgeographic.com/animals/mammals/bottlenose-dolphin/?source=A-to-Zl l(accessed 5 March 2013)

“Common Bottlenose Dolphin”, by Hogan, Michael C ,  Encyclopdia of Earth 2013. URL: http://www.eoearth.org/article/Common_bottlenose_dolphin?topic=49540l l(accessed 5 March 2013)

” Dolphins in Mythology”, by Bioexpedition.com, 2013. URL: http://www.dolphins-world.com/Dolphins_in_Mythology.html(accessed 5 March 2013)

“Introduction to Bottlenose Dolphin Aggressive behaviour”, by Discovery Commnications LLC, 2013. URL:

http://animal.discovery.com/mammals/bottle-nosed-dolphin-behavior-info.htm l(accessed 5 March 2013)