.jpg)
New Zealand Whales and Dolphins
Identification Of Whales And Dolphins
Identification Of Whales And Dolphins
The main problem in identifying cetaceans is knowing what features to take note of which will help to track the animal down back in the library or laboratory.
At sea one usually gets only glimpses of cetaceans and it is important therefore to take maximum advantage of each glimpse. In such cases, the important features to record are:
| 1. |
Size and shape of body. |
| 2. |
Size and shape of fins. |
| 3. |
Shape of beak and head. |
| 4. |
Colour pattern. |
| 5. |
Method of spout (height, angle, etc.). |
| 6. |
Method and frequency of surfacing (how much of the animal surfaces at one time; does it leap clear of the water, etc.). |
On the shore, whales and dolphins can of course be examined in greater detail and a number of measurements, and observations related to life history, can be obtained which can aid identification and also provide valuable data on the biology of these animals. The value of such measurements and observations can be greatly enhanced by saving the skeleton, particularly the skull and jaws. This may be done by burying the stranded cetacean in a well-marked grave on or near the beach for a few months, or by removing the head and suspending it in the sea in a mesh basket for sea lice to clean.
All measurements except the girth should be taken in straight lines and not over the curve of the body. A measuring tape, a length of string, and two dowels or battens are useful for taking long, straight measurements: one dowel is placed at the tip of the snout at right angles to the long axis of the body, and the tape or string extended from it to the point of measurement, or to the second dowel placed on that point.
Photographs of stranded cetaceans, particularly in colour, can be very valuable for identification and research, and the following views should be taken where possible: side and ventral views of the whole body, and close-ups of the head, fins, and genital region.
Data To Record
The following list contains only the most important items to record from stranded cetaceans. A more complete list may be found in the Journal of Mammalogy, Vol. 42, pages 471-76, 1961, in an article entitled “Standardized Methods for Measuring and Recording Data on the Smaller Cetaceans”:
page 44-
Species.
-
Date of stranding or capture.
-
Time of stranding or capture.
-
Locality.
-
Number of individuals.
-
Sex.
-
Observer.
-
Condition of specimen(s).
-
Remarks (circumstances of stranding etc.).
-
Number and longitudinal extent of throat grooves.
-
Number of teeth each side of jaw) — see Fig. 9.
-
Colour description (plus diagram or photograph).
Measurements
(see Fig. 8)
| 1. |
Length, total (tip of upper jaw to deepest part of notch between tail flukes). |
| 2. |
Length, tip of upper jaw to centre of eye. |
| 3. |
Length of gape (tip of upper jaw to corner of mouth). |
| 4. |
Length, tip of upper jaw to blowhole. |
| 5. |
Length, tip of upper jaw to anterior insertion of flipper. |
| 6. |
Length, tip of upper jaw to tip of dorsal fin. |
| 7. |
Length, tip of upper jaw to centre of anus. |
| 8. |
Girth, maximum (give distance from tip of upper jaw). |
| 9. |
Length, flipper (anterior insertion to tip). |
| 10. |
Width, flipper (maximum). |
| 11. |
Width of tail flukes (tip to tip). |
| 12. |
Depth of notch between flukes. |
| 13. |
Height, dorsal fin (tip to base). |
.jpg)
Figure 8: Standard measurements for smaller cetaceans.
Life History Data
| 1. |
External parasites (number and location). |
| 2. |
Internal parasites (nasal passages, stomach, etc.). |
| 3. |
Stomach contents (preserve in 10 per cent formalin or freeze if possible). |
| 4. |
Reproduction (presence of foetus, and milk in mammary glands in female). |
.jpg)
Figure 9: Tooth counts of cetaceans. The numbers refer to only one side of upper or lower jaws.