30 January 2013

Wet nurses in the whale world

Caring for the young is a global phenomenon, as is survival of the fittest. Social animals care for their young, usually within a family (or social) unit. What would stand out of the ordinary is when a family unit of one species cares for the young of other species. Mixed-species units are often observed during feeding migrations, notably of species that go after the same type of prey. But mixed-species family units are rarer.

A dolphin with a spinal deformity mills with sperm whales.
Photograph by Alexander Wilson and Aquatic Mammals

Recently, researchers in the Azores observed a social unit of  sperm whales which adopted a deformed adult bottlenose dolphin. One of the possible explanations for this rather rare behavior is that the dolphin is behaving like a sperm whale calf. Its deformity forces it to stay at the surface of the water, a behavior typical of whale calves which permits nursing females of the family unit to breast feed their young (Whitehead 2009). As family units often consist of females and their calves (Whitehead 2003), communally caring for their young (Best et al 1984), the adult (and small) bottlenose may have been taken in as a calf albeit of another species.

Best, P.B., Canham, P.A.S., and MacLeod, N. (1984). Patterns of reproduction in sperm whales, Physeter macrocephalus. Rep. Int. Whaling Comm. 6(Special Issue), 51-79.
Whitehead, H. (2003). "Sperm whales: social evolution in the ocean." University of Chicago Press, Chicago.
Whitehead, H. (2009). Sperm whale, Physeter macrocephalus. In Perrin, W.F.; Wursig, B.; Thewissen, J.G.M. 2009. Encyclopedia of Marine Mammals, Second Edition. Academic Press: London. 1316pp.

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24 January 2013

The Twilight saga continues under the sea

Nowadays we often associate the word “twilight” with “vampires”. Try searching the first word in Google and at the top of the list is The Twilight Saga: Breaking Dawn Part 2. In this context though, we are not going to talk about the epic book  (or movie) but about something that is also related to twilight – coral spawning.

The synchronized mass spawning of corals occurs annually, particularly only at twilight during a full moon. It is characterized by millions of minute particles being released into the water column, floating freely along the current, and forming a slick that extends meters wide and kilometers long and where fertilization takes place [1]. Factors that trigger this event are, viz.: chromatic changes based on the lunar cycle; temperature; and, day length [2]. Overlapping spawning times happen among species of corals. This was first documented in the Great Barrier Reef in 1981. And thus to achieve maximum fertilization success, as the law of nature dictates, different species respond similarly but independently to timing cues set by the factors said above [3]. Their spawning behavior may be analogous to pollination of plants but remember: corals are animals, not plants.

To learn more about the behavior of corals, visit SeaLifeBase.

“If your ship doesn’t come in, swim out to meet it!” – Jonathan Winters

[1] Thomas, A. 2002. Hard core spawn. ABS Science.
[2] Sweeney, A.M., C.A. Boch, S. Johnsen, and D.E. Morse. 2011. Twilight spectral dynamics and the coral reef invertebrate spawning response. Journal of Experimental Biology 214:770-777.
[3] Guest, J. 2008. How reefs respond to mass coral spawning. Science 320:621-623. 

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21 January 2013

Are you a dolphin? No I'm a whale...

Photo from the 11th Biennial Conference on the Biology of Marine Mammals

Wild animals are free-ranging, traveling hundreds of miles just to feed, mate, calve, and even to socialize. Worldwide, there are 124 marine mammal species belonging to the three main groups namely: Cetacea (83), Pinnipedia (36), and Sirenia (5).[1] These animals vary in size, shape, color, habitat and behavior, making them distinct from one another as seen in the picture above. It can be a wonder how else can we decipher which is which especially when we see them in the wild.

Photo from Baker (1999) [2]

For whales we can look at the direction and shape of their blows. While for other cetaceans and sirenians, we can take note of their habitat and behavior. To know more about the common behaviors of marine mammals, click here.

[1] Rice, D.W. (1998) Marine Mammals of the World Systematics and Distribution. Special Publication number 4: The Society for Marine Mammalogy. 231p.

[2] Baker, A.N. (1999) Whales and dolphins of New Zealand and Australia: an identification guide. Wellington: Victoria University Press, pp. 42–43.

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08 January 2013

2013 ushers in a new member of the SeaLifeBase team

The SeaLifeBase Project welcomes its newest member,

Ms. Elizabeth Bato.

Beth holds a degree on Agriculture and is currently on her 2nd year post-graduate studies on Environmental Science at the University of the Philippines Los BaƱos.

She will be handling distribution and occurrence data, thus her knowledge and experience on geographic information system (GIS) would be very helpful for this assignment.

Welcome aboard, Beth!

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