Subject: Whale Lifespan question.

Martine Berube (mberube@ulb.ac.be)
Mon, 11 May 1998 17:28:14 +0200 (MET DST)

Dear Danielle,
Here are my answers. Good luck with your project.

Martine

1 and 2-
The lifespan of the whales is very close to ours between 30 to 90 years old.
However, little is known on the subject. We can aged toothed whales
(dolphins, belugas, etc.) with growth rings in teeth and from long-term
population studies in which individuals are tracked by, for example,
photo-identification. However, for the baleen whale (blue whale, fin whale,
etc.) only long-term studies can give an estimate of their lifespan. For
small cetaceans, mainly toothed whales like dolphins, their lifespan was
estimated to 15-30 years. For the larger whales, like most baleen whales, it
was estimated to be between 40-90 years.  One example is found in one recent
paper, where a researcher described the discovery of an old-fashioned
whaling harpoon tip in a northern right whale. The  harpoon tip was made
about 70 years ago. In addition, the oldest known killer whale is a female
of over 80 years, and the oldest male killer whale was over 50 years old. 

3-
The most modern families of whales are known from the Miocene and one first
appears in the mid-Oligocene (30 million years ago). However, more archaic
whales, named the archaeocetes, are known from the Eocene (50 million years
ago). These archaic whales includes genera that illustrate the transition
from primitive terrestrial mammals.
4-
The blue whale and the right whale are being classified as endangered but
for more details I have pasted the following table.

POPULATION LEVELS OF DIFFERENT WHALE SPECIES
                            AND THEIR CLASSIFICATION
 
     (Sources: IWC; 1994.  Oceanus; Spring, 1989. NMFS; Endangered Whales
                           Status Update; June 1991)
     ________________________________________________________________
 
                        Population Estimates         Listing
     Species            Original :  Latest         US      / IUCN***
                        Level    :  Level         Govt.*
     ________________________________________________________________
 
     Blue Whale****       228,000:   14,000    Severely    /Endangered
                                               Depleted
 
     Fin Whale****        548,000:  120,000    Severely    /Vulnerable
                                               Depleted
     N. Atlantic Fin                 78,020                /Vulnerable
 
     Sei Whale****        256,000:   54,000    Severely    /Vulnerable
                                               Depleted
 
     Bowhead               30,000:    7,500    Severely    /Vulnerable
     Whale****                                 Depleted
 
     Sperm Whale****    2,400,000:1,950,000    At or Above /Insufficiently
                                                OSP*****        Known
 
     Right Whale****     ---      :   1,000    Severely    /Endangered
     (North Atlantic)                          Depleted
 
     (Southern            100,000:    3,000    Severely    /Vulnerable
     Hemisphere)                               Depleted
 
     Humpback             115,000:   10,000    Severely    /Vulnerable
     Whale****                                 Depleted
 
     Gray Whale****       >20,000:   21,000    Recovered   /Unclassified
 
     Bryde's Whale***     100,000:   90,000    Not Listed  /Insufficiently
                                                            Known
 
     Minke Whale          140,000:  941,240**  Not Listed  /Insufficiently
                                                             Known
 
     Atlantic
     Pilot Whale                    780,000    Not Listed    Not Listed
     ________________________________________________________________
 
     *According to the recent announcement by NMFS, US Dept. of Commerce.
     **Including 761,000 in the Southern Hemisphere estimated by IWC/SC in
     1990, re-affirmed in 1993.
     ***Status quoted from the IUCN Red Data Book, 'Dolphins, Porpoises and
     Whales of the World', 1991.
     ****Oceanus, spring 1989
     *****Optium Sustainable Pop.
Question:
>Dear sir,
>My name is Danielle Shaw, I am in the 4th grade at a school in Washington.
I have a science project due on the 13th, I  am doing my study on  whales,
and would like to know if you can answer me before then.. My question is this..
>
1-what is the average lifespan of the whale ?
2- Do each kind of Whale have different lifespans? 
3-How long has the Whale been on earth in general? 
4-And are they in danger of becoming extinct? 
>
>Thanks for answering my question.Danielle Shaw
Martine Berube
Unit of Evolutionary Genetics
Department of Molecular Biology
Free University of Brussels (ULB)
CP 244
Bld du Triomphe
B-1050 Brussels, Belgium
Tel: +32 2 650 5427
Fax: +32 2 650 5421
Email: mberube@ulb.ac.be