The categorization of the callosity pattern allows the matcher to look at just a small subset of the cataloged whales to find a match. When matching a photographed sighting to a cataloged animal, the matcher first reviews all the available information from the sighting and distill it into a series of codes that describe the callosity pattern and all other identifying marks. The matcher then searches the computer for cataloged right whales with similar attributes. In cases where the sighting information is unclear, the matcher will expand the search to include variations of particular attributes. For example, the matcher may categorize the lip callosity as large, but it may match a whale that has been coded as having a medium sized lip callosity.


          Catalog No. 1233                                           Catalog No. 1027                                                   View                                          

Callosity comparisonCallosity view

The callosity on the rostrum (or head) can be either “continuous” (one uninterrupted patch from the blowholes to the tip of the rostrum) or “broken” (see illustration above). However, because cyamids obscure the pattern and can move, some whales may appear to change from broken to continuous. Roughly 40 percent of the cataloged whales have continuous callosities and 60 percent have broken ones. (You can also view examples of the features and their codes here.)

In addition to the callosity on the rostrum, there may also be callosity tissue on the upper margins of the lower jaw (referred to as lip callosities), behind the blowholes (typically two patches, but can be one to four), on the chin, along the jaw or mandible and over the eye.

Categories of Callosity Patterns

To aid in the matching process (i.e. matching photographs of one sighting to an identified whale in the catalog), the callosity patterns are assigned categories that describe the spatial relationship of features within the pattern. The primary feature for categorizing broken whales is the number of “islands” and their placement relative to each other. Islands are discrete patches of callosity on the rostrum that are not connected to either the bonnet or the coaming. For continuous whales, it is the number and relative placement of “peninsulas.” Peninsulas are bulges along the outline of the callosity that interrupt a straight line.

For example, the broken whale in the illustration has two islands and the right one is forward of the left, its category is B6 - broken, two islands with the left island forward (full list of Categories and example images for each). If the two islands were side by side, they would be considered “symmetrical” and the category would be B4 - broken with two symmetrical islands. The continuous whale, known as “Admiral”, has 2 peninsulas with the left forward and is categorized as C5.

Cyamid covering can cause uncertainty in categorizing a whale’s callosity pattern. An island can appear to become “attached” to the bonnet or the coaming and a peninsula can seem to “disappear” due to a cyamid infestation (See example below). In these cases, the whale is assigned to several different categories in case the matcher misinterprets the underlying pattern.

December 2000

Categorization comparison with change over time - Dec. 2000

Erin LaBrecque/New England Aquarium

3 Months later

Categorization comparison with change over time - 3 months later

Alicia Windham-Reid/New England Aquarium

In addition to callosity patterns, right whales can also be recognized by other identifying marks.