There are several species of mammals listed under the Massachusetts Endangered Species Act, including whales, bats, shrews, and rodents. The conservation challenges facing these species vary dramatically between the groups.
Cape Cod Bay is globally significant for the North Atlantic Right Whale as a dependable source of zooplankton, on which the whales feed. On any given day in mid-winter, up to 25% of the 500 individuals that represent the entire species may be feeding in the Cape Cod Bay. The most frequent causes of mortality have resulted from ship strikes and entanglement in fishing gear, but great strides have been made to reduce both of these threats. The waters off of the Massachusetts coast, especially around Stellwagen Bank, are one of the top ten whale watching areas in the world. The Humpback Whales are the greatest draw because of their great tolerance for whale watching boats and their acrobatic behavior, including breaching, tail and pectoral flipper flapping, and sky-hoping. Fin Whales, and Minke Whales which are not state or federally listed, are also frequently seen. Less often seen are Sei Whales, Blue Whales, and Sperm Whales. All of these species suffer from ship strikes and fishing gear entanglement, but are benefiting from all of the work being done to help the Northern Right Whale.
All across North America, bats were affected by DDT and other pesticides, but for the past 40 years, their populations have been slowly recovering. The last hibernating group of Indiana Bats in Massachusetts was reported in a mine in the town of Chester in 1939. As their numbers slowly increased in New York and they returned to Vermont, there was great hope that they would soon be re-discovered in Massachusetts, as well. However, these hopes were dashed once White-nose Syndrome (WNS) was discovered in New York and the numbers of bat species that hibernate in caves and mines suddenly crashed. Not only did the Indiana Bat not return, but the most abundant bat species in Massachusetts, the Little Brown Bat, declined over 98%, to the point that it, along with the Northern Long-eared Bat, Small-footed Bat, and Tri-colored Bat (formerly the Eastern Pipistrelle), were listed as Endangered in Massachusetts in 2012. All five of the most important bat hibernacula are now closed to public access in order to protect the very few surviving bats from disturbance. Mass Wildlife acquired the two most important mines and has gated them with specially designed bat gates that allow the small bats to freely fly through, while keeping people out. Research is underway to better understand the fungus that causes WNS, but currently there is no known way to prevent it or effectively treat it.
Due to severe population declines, the U.S. Fish & Wildlife Service listed the Northern Long-eared Bat in April 2015. To assist project proponents in complying with the 4(d) rule, the NHESP is providing a map for known locations of winter hibernacula and maternity roost trees.
Shrews and Rodents
Very little is known about the three state-listed small mammals in Massachusetts. The Rock Shrew is a habitat specialist, found at higher elevations, especially in areas of rock jumble below exposed rock ledges. This shrew was first found in Massachusetts in 1911 on Mt. Greylock and since then, only nine individuals have been documented at three locations in Berkshire County. Although there are very few records, this small shrew lives below ground most of its life and is very difficult to find unless specifically looked for. As long as these areas of higher elevation habitat remain protected, this shrew will probably remain secure. Another shrew, the Pygmy Shrew (not state-listed), which is the smallest mammal in Massachusetts, has only been found once in the state, but is probably also secure in these areas of protected habitat. The only specimen documented in Massachusetts was found drowned in a discarded beer bottle in 1991 on Mt. Greylock. The Water Shrew is also secretive and difficult to find, but has been documented in six counties in central and western Massachusetts along the edges of streams and beaver swamps. The Wetlands Protection Act serves well to protect the habitat of this species.
For species-specific status and life history information, please view our Rare Species Fact Sheets .