Guide

Look closerMammals

Muskrat push-ups: plant mounds on marsh ice

December to February

When a cattail marsh or pond freezes, muskrats gnaw holes in the ice and push plants up through them into small dome-shaped mounds called push-ups. Look for dark lumps on the ice from the bank: each one is a rest stop and feeding spot for a muskrat swimming below.

Why this time of year

Once a marsh or pond edge has frozen over, muskrats are working under the ice and keeping their push-ups open by using them again and again.

How to notice it

  1. Stay on the bank or shoreline path and scan the frozen cattail edge, ideally with binoculars, for small dark dome-shaped lumps sitting on the ice.
  2. Compare what you see: a push-up is a low mound of marsh plants and mud on the ice surface, while a lodge is a bigger, firmer pile of cattails and mud resting on the marsh bottom.
  3. Look for several push-ups spaced out across the same marsh. Each one usually has room for just one muskrat, and they can sit far out from the lodge.

Try this with kids: From the bank, count the dark lumps on the ice with your eyes or binoculars, and guess which one a muskrat might pop up in for a snack and a breath of air.

Word to know: A “push-up” is a small dome of marsh plants a muskrat piles over a hole it gnawed in the ice.

Safety

  • View from the bank only. Never walk or step onto ice to reach or get a closer look at a push-up. MassWildlife says there are no guarantees and to always consider ice potentially dangerous.
  • Keep children and dogs on shore and give the animals space.

Sources

  • mass.govMassWildlife (published 2025-05-01), opened by the lead in the browser pane on 2026-10-30 after the sourcing agent got 403. Quotes: 'commonly found in ponds, lakes, and marshes in Massachusetts'; 'Muskrats are active year-round in Massachusetts but will burrow deeper in the winter'; 'Muskrats are common throughout Massachusetts, but populations have been declining range-wide for more than 10 years'; listed as a Species of Greatest Conservation Need (MA State Wildlife Action Plan). Page does not mention push-ups or ice.
  • northernwoodlands.orgNorthern Woodlands (New England nature column). Push-up appearance and construction; how they differ from lodges; use as eat, rest and breathe spots. Quotes: 'dome-shaped mounds of marsh plants that cover holes in the ice'; 'gnaw four- to five-inch diameter holes and push marsh plants up through the ice'; lodges 'rest on a firm base'; 'eat, rest and catch a breath of air'.
  • adfg.alaska.govAlaska Dept of Fish and Game (revised 2025). Push-ups are piles of vegetation on the ice over an opening, where muskrats eat, breathe and rest; repeated use keeps them free of ice; they can freeze solid in cold, low-snow winters. Quote: 'pushups which are piles of vegetation deposited on the surface of the ice over an opening'.
  • hww.caCanadian Wildlife Federation / Environment Canada factsheet. Push-ups form shortly after freeze-up, are miniature lodges with room for one muskrat, used as resting place and feeding station. Quote: 'Shortly after freeze-up, muskrats chew holes through the ice in bays and channels up to 90 m away from the lodge to create push-ups.'
  • portal.ct.govConnecticut DEEP. Muskrats active year-round, spend more time in dens in winter, small feeding huts may be built in their territory. Does not mention ice or push-ups.
  • cambridgeday.comLocal newspaper (not roster, corroboration only). Massachusetts presence and under-ice feeding: 'live in most of the shallow lakes, ponds, slow rivers and swamps in Massachusetts'; 'If their pond freezes over in winter, they feed under the ice and sometimes eat their push-ups.'
  • mass.govMassWildlife ice strength and safety page, opened by the lead in the browser pane 2026-10-30: 'There are no guarantees. Always consider ice to be potentially dangerous.' Backs the safety note.

Checked against these sources on October 30, 2026.

In the guide for December, January, February

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