IDENTIFY THE WHALES
The resident sperm whales of Dominica live in stable, matriarchal, family-oriented communities called social units that are composed of three to twenty individuals. The groups are structured around the care and protection of their dependent young, and every whale has a special place in the social network.
Social groups live cooperatively and perform all of their daily functions together as a unit. For sperm whales, being together means remaining in constant contact via sound. They travel, sleep, socialize, rest, and hunt together. The adults share responsibilities for feeding, protecting, and conveyance of language and cultural knowledge to the group’s offspring.
Each unit is defined by its own language markers, and every individual within the family is differentiated through a specific acoustic signature. Family units who reside in the same vicinity and share a specific dialect comprise a broader social group called a clan. There are two resident clans in the Eastern Caribbean. The most commonly viewed clan off the coast of Dominica has nearly two dozen families, while the other contains a much smaller number of families who are rarely seen.
Social units are organized to support the optimal care and protection of dependent calves. While each whale has a special place within the social network of the family group, their roles and responsibilities are ever changing. The female elders pass important cultural information from generation to generation, however the calves assume the central role in the social network of the units.
Relationships among the whales are fluid and social prominence within the units is based on age, their status as mothers, and the age and needs of their offspring at a given time. The more involved females are in the direct cartaking of the calves, the more central they are to the social structure.
The social dynamic of the unit changes each time new calves are welcomed into the family. Newer mothers can become temporarily more isolated, likely due to an increase in hunting activity required to meet caloric demands to support nursing. Babysitting responsibilities are spread among all members of the unit, but there tends to be one primary sitter for each calf. When the unit has several similarly aged calves there is often a primary group sitter.
As with any population, the size of the social units fluctuates over time. The number of members that comprise a group can change as a result of death, adolescent males leaving the family, and the addition of new calves. If the unit size dwindles, the members may combine with another group to form a blended or generally (vs strictly) matrilineal or matrilineally-based unit. The composition of the family also changes as dependent calves mature to become juveniles and eventually adults.
Although social positions shift within the units, a central matriarchal figure typically emerges who appears to establish the general tone and temperament of the group. This role is impermanent but nevertheless has an impact on the behavior of the unit. In larger, blended-family groups the central matriarchal role may be shared among compatible elders. No matter who is setting the tone at a particular time, the affectionate, life-long bonds maintained by the females solidify the cohesiveness of the units, each of which reflects a harmonious and ever-changing blend of the unique personalities of its members.
The comprehensive underwater catalog system we have created enables us to confirm positive identification of numerous whales and social units, and is proving to be a valuable instrument for monitoring the expansion and contraction of resident families. When we are fortunate to do so, the ability to see these whales on multiple, consecutive days enables us to develop a sense of the relationship dynamic within the social unit. In addition, the video footage we have collected over the past ten years helps us recognize behavior and body language that instantly differentiates certain whales.
We have found some individuals and social groups to be congenial and interactive with us while others tolerate our presence with mild indifference. A few of the whales are wary of humans and only allow viewing from afar. At all times, we respect and prioritize the welfare of the whales, adjusting our behavior in relation to their tolerance of our presence and willingness to be observed.
It is a privilege to spend time in the water as citizen scientists to document the sperm whale families who frequent the coast of Dominica. We are extremely grateful to the government of Dominica and specifically to the Department of Fisheries for enabling us to work under permit to enter the water with the whales.
Here are the social units of the Eastern Caribbean clans we have thus far had the pleasure of identifying:
Unit A
Unit A is among the largest, friendliest, most interactive and well documented social units in Dominica. This group is composed of two strict matrilines that together consist of six adult females, two female juveniles, and four dependent calves. Adolescent male Allan appears to have departed the group at thirteen years old in early December, 2021.
All six of the adult females have reproduced and two of them, Lady Oracle and Fruitsalad, have grand-offspring. The group appears to have welcomed three new male calves into their blended family as of late 2021. Two of new mothers, Atwood and Snow Woman, were extremely active in caretaking roles in the years prior to giving birth. We have yet to confirm the parentage of the third calf.
We first observed members of Unit A in 2012, and over the past decade we have witnessed them exhibit a wide variety of behaviors. The whales from this group have consistently proven to be extremely cooperative and tolerant of our presence in the water as they go about their daily routines. The three calves we met in 2016 show a particularly high degree of ease, trust and familiarity with us each year.
Unit R
Unit R has been regularly observed off the island of Dominica for the past seventeen years. There may be up to nine members in this social group, however we usually see them in smaller groups of 5 – 7 individuals at a time.
The whales from this social unit appear to be relatively comfortable, relaxed, and familiar with researchers as we enter the water in their vicinity and record their behavior. A few of the members are very friendly and interactive, while others are tolerant of our presence if not actively engaging.
Rip and her daughter Rap have been the most congenial of the group, and Rap has initiated lively contact with our team on several occasions. Unit R is slowly expanding with the birth of Rap’s new calf in 2021.
Thus far we have documented seven of Unit R’s whales.
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Unit U
Unit U is comprised of five members including Knife, Fork, Hope, Canopener, and a yearling calf born in 2020. This social group is widely considered to be part of a blended unit, having formed a bond-group with whales from Unit F.
The individuals in Unit U tend to be somewhat timid with the exception of Canopener who is one of the more personable and engaging whales we encounter in Dominica. However, when the social units merge to form a collective group, even the most standoffish whales grow bolder and are more amenable to our documentation efforts.
We collected excellent footage of the blended unit while they were in motion during our 2019 field season. The whales were exceptionally relaxed and tolerant of our presence over the course of an extended encounter. Canopener and Hope were particularly gregarious and engaging, often gliding within feet of our citizen scientists as we swam and filmed the group at a relaxed pace.
Unit U has expanded with the addition of Canopener’s new calf who was welcomed into the family in 2020. We caught a fleeting sight of Canopener and her calf traveling with Pinchy in 2021, and we were pleased to note that whales from Units U and F still form a blended group.
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Unit F
Unit F has been the subject of scientific investigation since 1995, and is considered to be the best-studied social group in the world. Researchers from the DSWP initially named this unit the Group of Seven, however their numbers have dwindled over the years. There are presently three whales in Unit F including Fingers, Pinchy, and Digit.
This family group has had a long and close affiliation with Unit U, dating as far back as 2008. The two units can often be seen together traveling, socializing, and affectionately caring for one another’s offspring.
We experienced an extended, flowing encounter with members of Units F and U in 2019 that enabled us to observe their behavior and obtain a sense of their intrinsic nature as a blended bond-group. The whales were calm, relaxed, generous, and cooperative with observers despite the windy day and choppy seas. After witnessing a series of tentative flybys from afar, we gained the whales’ trust and they allowed us to track their movement as they swam between rest stops. This allowed us to document some of the shier, more reserved members of the combined group.
During our 2021 field season we briefly observed Pinchy and Canopener swimming rapidly offshore, providing confirmation that the two groups continue to perpetuate their close affiliation.
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Unit J
Unit J is a small social group who is often seen with Units D and A. In recent years, only four members had been regularly observed and recorded near to Dominica including Jocasta, Sophocles, Jonah, and Laius.
As of 2021, the unit appears to have grown significantly with the addition of two new offspring. Laius and Jocasta were each seen with very young calves. Laius’ calf is a male, and we have yet to confirm the gender of Jocasta’s calf although we strongly suspect her to be female. In the meantime, Jonah appears to have taken on the role of a playful caretaker of the newest members of the unit.
We documented whales from Unit J swimming with Unit D on Nov 23, 26, and 27 of 2021.
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Unit D
Unit D is a mid-sized social unit consisting of five or six whales. Members of this group have been recorded through photo identification in the waters surrounding Dominica since 1984.
As of 2021, Unit D has returned to the vicinity of Dominica after being absent for approximately six years. Prior to 2014, members of Unit D were regularly found intermingled with whales from Units A and J. Consistent with their past behavior, they continue to associate with friends from these two units.
We documented adults Drifter, Drop, and a male small calf socializing with Unit A on Nov 22, 2021. Days later we observed Doublebend, Drop, and the calf swimming in a blended group with members of Unit J. Both of these social groups appear to have added calves to their families, and we have assigned parentage for the small male calf to Drop pending DNA confirmation.
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Unit S
Unit S is a very small but easily recognized social group that for a number of years consisted of only three to four whales. Members of this unit have been known to spend a great deal of time with whales from Unit R.
We are pleased to report that Unit S appears to have welcomed a new addition to their family. Sally was seen swimming with a young calf in the company of members of Unit R on Dec 10, 2021.
