There are 77 species of mammals known to occur regularly in the NWT, beside humans. One species, the European rabbit, is alien. Eleven additional species are vagrant, and another species, the eastern red bat, is expected to occur in the NWT.

Vertebrates

Vertebrates are animals with backbones. They have bilateral symmetry, as well as a circulatory and nervous system. They include the most studied species in the NWT as many are central to our cultural and economic health. Humans (Homo sapiens) are a member of this group.

Mammals have warm blood, a placenta, and feed their young milk. Some mammals are mostly terrestrial, and some have returned to the ocean, and live exclusively in the sea. All the mammal species present in NWT, beside humans, are included in the NWT General Status Ranks.

Terrestrial Mammals

Terrestrial mammals include some of the most iconic and important species to people’s well-being in the NWT. They are central to our cultures and economies as a source of food, clothing, and tools, as well as spiritual connections to the land. The importance of mammals to people and to northern ecosystems explains why a substantial amount of time and resources are invested in their study and monitoring.

In the past five years, most detailed assessments were conducted for terrestrial mammals, recording increasing risk of extirpation. Although some herds are now stable in numbers, all ecotypes of caribou in the NWT are at some risk of extirpation. Caribou is the most monitored of all terrestrial mammals in the NWT. In the NWT, many agencies, boards, communities, renewable resources councils, and knowledgeable people are working together to monitor species and ensure all mammals remain part of our rich northern biodiversity.

Traditional knowledge studies are conducted every year on mammals. In 2021, the Species at Risk Committee adopted an exciting new way to assess the conservation status of species, including mammals, using criteria specifically adapted to be used based on traditional knowledge. Indigenous, community, and scientific knowledge provided the basis for all the ranks presented in the next pages.

Genetic studies continue to result in major changes in taxonomy, including in mammal taxonomy. The NWT General Status Ranks follow these new findings and now groups terrestrial and marine mammals, and places whales with their genetic relatives, the ungulates. A new name for artiodactyla to cetartiodactyla reflects this change. More changes in taxonomy are expected with further advances in molecular studies.

Marine Mammals

Marine mammals are fully adapted for life underwater, are streamlined for swimming, and can dive for long periods of time, although they must surface to breathe.

Marine mammals of the NWT have special adaptations for life in the Arctic. For example, beluga whales lack a dorsal ridge and are white in colour, which helps them travel through sea ice and evade their main predator, the killer whale. Belugas winter in the Bering Sea and migrate through leads in sea ice to their summering grounds in the Beaufort Sea. Beluga from the eastern Beaufort Sea stock form one of the world’s largest beluga summering congregations in the Mackenzie Estuary, where they are a key harvested species for the Inuvialuit. Belugas are toothed whales (Family Monodontidae) that feed on a variety of fish and invertebrates and find prey using echolocation. They have a thick layer of blubber that insulates them from the cold. Belugas are highly vocal, social animals that use different types of calls to communicate.

Two groups of marine mammals occur in the NWT portion of the Arctic Ocean – the eastern Beaufort Sea: pinnipeds (infraorder Pinnipedia) and cetaceans (infraorder Cetacea). Pinnipeds are claw-footed carnivores including seals (Family Phocidae), sea lions (Family Otariidae), and walruses (Family Odobenidae). Ringed seals and bearded seals are year-round residents widely distributed throughout the eastern Beaufort Sea. Other pinnipeds are vagrant and occur infrequently. There are only two cetacean species that are regular seasonal migrants to the NWT; these are the beluga and bowhead whales. In addition, gray whales and killer whales have been recorded on occasion in NWT waters and have been observed more frequently in recent years. Narwhals have not been reported from the area in recent decades and are considered to be extremely rare.

Marine mammals are an important cultural and food resource for Inuvialuit hunters and their families. Harvest monitoring and research supports population and ecosystem assessments to ensure that marine mammal stocks are stable and healthy for future generations.

Two marine protected areas in NWT waters are key conservation tools to protect marine mammals and their habitats. Climate change is a significant stressor for ice-associated Arctic marine mammals. Changes in sea ice impact the availability of sea ice habitat, affect whale migration routes and timing, and may lead to changes in prey availability and quality. Increased vessel traffic throughout the Arctic region is increasing underwater noise; this has potential to mask marine mammal communications, lead to hearing damage, and potentially alter behaviour and life history activities. More frequent sightings of killer whales and gray whales may increase predation and competition amongst some marine mammal species. The cumulative ecological impacts of these multiple stressors are not fully known and remain a key area of study.

Marine mammals are considered to be sentinel species for detecting ecosystem change because they are long-lived and near the top of the food chain. In the NWT, tissues from beluga whales and ringed seals are collected as part of long-term harvest-based monitoring and provide information on contaminant levels, disease, and diet of these key species.

Current research on marine mammals in the NWT includes documenting habitat use, movements, and behaviour with satellite tracking and photographic aerial surveys. A growing network of passive acoustic monitoring sites is being used to characterize the underwater soundscape to assess future impacts of anthropogenic noise on marine mammals. Involvement

of northerners in co-management, research, and monitoring is an important aspect of science. By working together, scientists and Indigenous Knowledge holders are providing much needed information to manage for healthy marine mammal stocks in the NWT.