Subject: Pilot whales

Lindsay J Porter (h9390327@hkucc.hku.hk)
Tue, 7 Apr 1998 08:58:49 +0800 (HKT)

>I have to do a report on pilot whales.  I don't know much about them.  Can you
>send me some information?

PILOT WHALES
The following site has  a good account of the species. 
http://www.oit.itd.umich.edu/bio/doc.cgi/Chordata/Mammalia/Cetacea/Delphinid
ae/Globicephala

There are two species of pilot whale;
Globicepala melas - the long finned pilot whale 
Globicephala macrorhynchus - the short finned pilot whale

Long finned pilot whales are found in temperate and sub-polar zones, in
both oceanic and some coastal waters.  Those populations found in southern
waters are isolated from those found in northern.  Long-finned pilot whales
are highly social - occurring in groups of 20, 100 to over a 1000
individuals.  These groups are stable over long time periods.  The species
displays sexual dimorphism - females being 5.7m in length nand males 6.7m -
and males can weigh as much as 2000kg.  Their diet consists of squid and
'medium-sized' fish, which they dive to great depth to catch.  This species
often forages in  ranks - sometimes with other species.  Although the
species quite often displays above water, groups are quite often seen
'rafting' on the surface - presumabley resting. 

Both species have extremely long tappered flippers and are dark brownish
grey to black in colour.  Males have a more bulbeous head than females and
it is difficult to distinguish the two species in areas where populations
overlap - the long-finned has a longer dorsal fin cf. to the short-finned
(intuitively enough!)  Long-finned have a light grey saddle patch behind the
dorsal fin - as do short-finned but in addition, short finned have a pair of
parellel light bands on its back, extending from eye to saddle patch.
 
BOTH species are classed by the IUCN as "Insufficiently known"  and threats
to  long-finned pilot whales include drive fisheries in the Faroe Isles and
incidental catch in the western north Atlantic and the Mediterranean.

Short-finned Pilot Whales

Look on Song of the Whales website for info on their studies on
short-finned pilot whales and pictures

http://www.ifaw.org/pilot.htm
(Copy of text from Song page)

Size : Adults grow up to 5.5m (females) and 6.1m (males), and adult males
may weigh up to 3,600kg. They are about 1.8m long at birth.

Geographical Distribution : Found in warm temperate and tropical waters
worldwide, these odontocetes are not usually found north of 50 degrees, or
south of 40 degrees. Outside this range, their niche is filled by their
long-finned relatives,

Globicephala melas, the long-finned pilot whales.

Exploitation : Pilot whales have been hunted by coastal fisheries
throughout their range. The largest recent catches have occured off Japan,
where coastal whale fisheries account for a few hundred annually and in the
Caribbean.

Pilot whales are a highly social species with a wide vocal repertoire. They
dive deep to feed, it is thought predominantly, on the squid they find
there. Their complex social structure includes females suckling the young of
their relatives, for up to 15 years after they become post reproductive at
an age of about 35 years. The extremely tight bonds of this matrilinear
social structure may account for the frequent mass strandings involving
pilot whales.

best wishes
Lindsay J Porter

email h9390327@hkucc.hku.hk
Dolphin Research Group
The Swire Institute of Marine Science
The University of Hong Kong
Cape d'Aguilar
Hong Kong
website: http://www.webdivers.co.uk/dolphin/index.html