Female Narwhals and Beluga Whales Go Through Menopause, Too


While menopause is a fact of life for middle-aged women, it's exceedingly rare in the animal kingdom. Including humans, there are now five mammal species that experience it.

As Forbes reveals, a new study in the journal Scientific Reports finds that female narwhals and beluga whales also go through menopause as they age. Until now, only three other species—humans, killer whales, and short-finned pilot whales—were known to experience this reproductive phase and continue to live a long time afterward. 

Drawing from past research, scientists at England's Exeter and York Universities and the Center for Whale Research in the U.S. set out to discover whether menopause occurred in other marine mammal species. After examining the ovaries of 16 species of whales and dolphins, they identified narwhals and beluga whales as the only other animals that experience menopause.

Menopause refers to the period in which menstruation permanently ceases and females are no longer able to reproduce. Unlike humans and the four aforementioned whale species, most females in the animal kingdom are able to continue reproducing well into old age. This group includes elephants, which have some of the longest lifespans of any animal on Earth.

This is an oddity that has puzzled scientists for years. "For menopause to make sense in evolutionary terms, a species needs both a reason to stop reproducing and a reason to live on afterwards," one of the new study’s authors, Samuel Ellis of the University of Exeter, tells Forbes.

Previous research on killer whales (which were not included in the scope of this study) suggest that menopause is linked to grandmother whales’ relationships with their young offspring—a theory called the “grandmother hypothesis.” Ellis notes that “both male and female [killer whale] offspring stay with their mothers for life—so as a female ages, her group contains more and more of her children and grandchildren.”

The whale’s children and grandchildren are all competing for resources such as food, so that may be why menopause steps in to shut down her reproductive cycle. It's believed that grandmother whales continue to live on well after menopause—unlike other species that go through something like menopause, but die shortly after—because they provide crucial knowledge to their close-knit groups of descendants. The authors of the latest study say there is also evidence that our human ancestors followed similar social patterns.

[h/t Forbes]

Wayfair’s Fourth of July Clearance Sale Takes Up to 60 Percent Off Grills and Outdoor Furniture


This Fourth of July, Wayfair is making sure you can turn your backyard into an oasis while keeping your bank account intact with a clearance sale that features savings of up to 60 percent on essentials like chairs, hammocks, games, and grills. Take a look at some of the highlights below.

Outdoor Furniture

Brisbane bench from Wayfair

- Jericho 9-Foot Market Umbrella $92 (Save 15 percent)
- Woodstock Patio Chairs (Set of Two) $310 (Save 54 percent)
- Brisbane Wooden Storage Bench $243 (Save 62 percent)
- Kordell Nine-Piece Rattan Sectional Seating Group with Cushions $1800 (Save 27 percent)
- Nelsonville 12-Piece Multiple Chairs Seating Group $1860 (Save 56 percent)
- Collingswood Three-Piece Seating Group with Cushions $410 (Save 33 percent)

Grills and Accessories

Dyna-Glo electric smoker.

- Spirit® II E-310 Gas Grill $479 (Save 17 percent)
- Portable Three-Burner Propane Gas Grill $104 (Save 20 percent)
- Digital Bluetooth Electric Smoker $224 (Save 25 percent)
- Cuisinart Grilling Tool Set $38 (Save 5 percent)

Outdoor games

American flag cornhole game.

- American Flag Cornhole Board $57 (Save 19 percent)
- Giant Four in a Row Game $30 (Save 6 percent)
- Giant Jenga Game $119 (Save 30 percent)

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

The Reason Your Dog Follows You Everywhere

Crew, Unsplash
Crew, Unsplash

Depending on your mood, a dog that follows you everywhere can be annoying or adorable. The behavior is also confusing if you're not an expert on pet behavior. So what is it about the canine companions in our lives that makes them stick by our sides at all times?

Most experts agree on a few different reasons why some dogs are clingy around their owners. One is their pack mentality. Dogs may have been domesticated thousands of years ago, but they still consider themselves to be part of a group like their wild ancestors. When there are no other dogs around, their human family becomes their pack. According to Reader's Digest, this genetic instinct is also what motivates dogs to watch you closely and seek out your physical touch.

The second reason for the behavior has to do with the bond between you and your pet. As veterinarian Dr. Rachel Barrack told the American Kennel Club, puppies as old as 6 months can imprint on their human owners like they would their own mothers. Even older dogs will bond with the humans in their lives who show them care and affection. In these cases, a dog will shadow its owner because it sees them as an object of trust and security.

The last possible explanation for why your dog follows you has more to do with your treatment of them than their natural instincts. A popular training tactic is positive reinforcement—i.e. rewarding a dog with treats, pets, and praise when they perform positive behaviors. The point is to help your dog associate good behaviors with rewards, but after a while, they may start to associate your presence with rewards as well. That means if your dog is following you, they may be looking for treats or attention.

A clingy dog may be annoying, but it usually isn't a sign of a larger problem. If anything, it means your dog sees you in a positive light. So enjoy the extra companionship, and don't be afraid to close the door behind when you need some alone time.