Is National Nana Day an official or public holiday?

No. It is an unofficial observance with no documented founder, so it is a normal working day and nothing closes for it.

What is the grandmother hypothesis?

It is the leading-but-debated idea that older women boosted their grandchildren's survival, which over time may have selected for the long human lifespan past fertility. Researchers treat it as influential, not settled.

Why is it called Nana?

Nana is a reduplicative nursery word, the kind of soft doubled sound small children produce easily. It entered English by 1844 as a child's name for a grandmother or nurse.

National Nana Day

Next celebratedSaturday, April 10, 2027

Nana's day comes with a hypothesis attached; humans may live decades past childbearing because grandmothers who fed their grandchildren boosted the odds those children survived.

See how to celebrate

Countdown to the day

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Last updated August 30, 2026 · by the Holiday Calendar TeamHave an update or spot an error?

YEARLY DATEApril 10

OBSERVED INInternationally

CATEGORYRelationships

SUBCATEGORYFamily

ORIGIN

Community Origin

FOUNDING ENTITY

Not documented

FIRST OBSERVED

Not documented

HOW THE HOLIDAY CAME TO BE

Kept by grandchildren's posts, not by an organisation.

National Nana Day circulates through holiday-listing sites and recurring social posts honouring grandmothers called Nana. No proclamation, registry filing, trademark or founder announcement documents who created it or when.

+ Know the story? Submit a founder Help us complete this holiday

INTRO

The radical idea that grandmothers built the human lifespan

Here is a possibility that unsettles a lot of people the first time they hear it. Humans may live for decades after they can no longer have children because of grandmothers. National Nana Day, observed every April 10, lands on the warm side of an idea whose science is stranger than the card aisle lets on.

In 1998, a team led by anthropologist Kristen Hawkes proposed what became known as the grandmother hypothesis. The argument runs that older women who stopped reproducing and instead fed their daughters' children boosted those grandchildren's survival. Over many generations, the researchers argued, that help selected for a long life that outlasts fertility.

The gap is real. In the same 1998 data, humans logged far more years of adult life than chimpanzees or gorillas did, and most mammals breed nearly until they die. A woman, by contrast, can live half her life after her last child.

The hypothesis is influential, and it is also still contested, which is part of what makes a day for Nana more interesting than it looks. A note on the date: April 10 also carries National Siblings Day, and the September day for grandparents is a separate, documented observance.

ORIGINS

Nana Day history

INTRODUCTION

Start with the word, because the word came long before the day. "Nana" is a baby's word. It is the kind of soft, doubled sound that small children produce almost anywhere, which is why kin terms like it keep surfacing in unrelated languages.

English first wrote it down in 1844, as a child's name for a grandmother or a nurse, per the Online Etymology Dictionary. It sits close to "nanny," attested back in 1795 for a female adult who was not your mother. The day inherits all of that affection without inheriting a paper trail.

CHAPTER 01

The biologist who reframed menopause

For a long time, a long post-fertile life looked like a defect. In 1957, the biologist George C. Williams suggested the opposite. He argued in the journal Evolution that menopause could be an adaptation.

His point was that an aging female might gain more by protecting the children she already had than by risking another birth. Williams did not yet talk about grandchildren. That leap came later.

CHAPTER 02

The Hadza, digging in the dirt

The leap came from fieldwork in Tanzania. Among the Hadza, hunter-gatherers studied by Hawkes, O'Connell and Blurton Jones, the hardest foragers were not young mothers. They were the older women.

Post-childbearing women foraged more than seven hours a day, far more than the women still raising infants. They went after the deep, stubborn tubers that small children could not dig, and they fed the grandchildren when new mothers had their hands full. The grandmother was not a bystander but a provisioner of the next generation.

CHAPTER 03

A day with no birth certificate

National Nana Day has none of that documentation. No proclamation, no trademark, no founder stepping forward to claim it.

It surfaces on holiday-listing sites and in April 10 social posts that tell people to call their nana. The honest account is that the subject is ancient and the observance is recent and untraceable. The grandmother is centuries deep in the record, while her appreciation day is a modern, organic add-on, and a warm one.

WHY THIS DAY MATTERS

Why We Love National Nana Day

ECONOMY

Roughly $900 billion a year in care, by AARP's count.

AARP reports that about 69 percent of grandparents provide some care for grandchildren, and values that unpaid care plus direct financial help at roughly 900 billion dollars a year. The day puts a name on labor that mostly goes uncounted.

LONGEVITY

Caregiving tracks with a longer life

A 2017 study of older Berlin adults found that grandparents who helped care for grandchildren had lower mortality than those who did not. The researchers framed it as an association partly explained by health, not as proof that babysitting extends your life.

LANGUAGE

It honors a specific name, not a category

Most grandparent days speak in the generic. This one names the woman the way a grandchild actually addresses her, which is a small but real difference in how a tribute lands.

TIMELINE

Timeline

"Nanny" enters English

The word is first attested as a child's term for a female adult other than the mother.

"Nana" first attested

English records the reduplicative nursery word for grandmother or nurse.

Williams seeds the idea

Biologist George C. Williams proposes that menopause could be an adaptation, not a flaw.

Grandparents Day made federal

President Carter signs Proclamation 4580 for the separate September observance.

Grandmother hypothesis formalized

Hawkes and colleagues publish the full argument in the journal PNAS.

Orcas echo the pattern

A study finds post-reproductive killer whale grandmothers raise grandcalf survival.

MYTH VS FACT

Common Misconceptions

The myth

A long life after menopause is a uniquely human design flaw.

The truth

Many researchers treat it instead as a leading-but-debated adaptation, the idea that a long post-fertile life could itself have been favored because of the help older females gave their kin.

The myth

Scientists agree grandmothers explain the human lifespan.

The truth

The grandmother hypothesis is influential but contested, with rival accounts like the mother hypothesis and the embodied-capital model still in play, and a 2017 simulation favoring a role for cognition alongside grandmothering.

GOOD TO KNOW

National Nana Day Around the World

Spain and Latin America

Abuela, the everyday word for grandmother

Germany and the Netherlands

Oma, short and affectionate

Russia

Babushka, which also means old woman

Italy

Nonna, said by grandchildren across the country

Greece

Yiayia, said warmly across generations

Korea and Japan

Halmoni in Korean, Obaachan in Japanese

AT A GLANCE

Nana, the grandmother, at a glance

What it means: A child's word for grandmother
First attested: 1844, in English
Closest relative: "Nanny," attested 1795
US popularity: Among the most-used grandmother names
UK reach: Dominant in much of England, rare in Scotland
Word origin: Reduplicative nursery sound

BY THE NUMBERS

National Nana Day by the Numbers

32.9 yrs: Human adult lifespan in forager data
17.9 yrs: Chimpanzee adult lifespan, forager data
~15%: US grandparents giving near-daily care
511 hrs: Care per grandparent each year, AARP
~65M: Grandparents in the United States

GOOD TO KNOW

Surprising facts about National Nana Day

Losing grandma is dangerous for orcas

A 2019 study found a killer whale grandcalf faced about 4.5 times higher mortality risk after its post-reproductive grandmother died, and the effect was worst in low-salmon years.

Church ledgers proved the grandmother effect

Researchers mined 18th and 19th century Finnish and Canadian parish records and found women with longer post-reproductive lives ended up with more surviving grandchildren.

Menopause evolved more than once

Humans are not the only species with a real post-reproductive life. Several toothed whales, including killer whales, belugas and narwhals, evolved their own menopause independently, in lineages far removed from ours.

The grandmother effect favored the younger grandmas

In the historical parish data, the survival boost was strongest when grandmothers were under about 60 and the grandchildren were roughly two to five years old, the window when an extra pair of hands mattered most.

A nana can outlive her fertility by decades

Maximum human lifespan runs close to a century, yet female fertility ends near the halfway mark, a gap that almost no other mammal shows.

GET INVOLVED

How to Celebrate National Nana Day

Call the nana in your life

Pick up the phone instead of sending a text on April 10. The day grew out of simple social posts telling people to do exactly this.

RECORD

Record her story before it fades

Sit her down and capture how she met your grandfather, or what her own nana was like. A voice memo on your phone is enough to keep it.

COOK

Cook the dish she is known for

Make the recipe everyone associates with her kitchen, even if yours comes out wrong. Send her a photo of the attempt.

LEARN

Learn her name in another language

Try Abuela, Oma, Nonna, or Halmoni and see which one makes her laugh. Picking the version her own family used is an easy way to make the day feel personal.

HAND

Hand a grandchild the camera

Let a kid interview their nana and ask whatever they want. The unscripted questions tend to pull out the best answers.

Test your knowledge

How well do you know National Nana Day?

1 / 9

What does the grandmother hypothesis propose?

Answer

No. National Grandparents Day is a separate, documented observance on the first Sunday after Labor Day in September, created by President Carter's 1978 proclamation. National Nana Day is its own April 10 day with no documented origin.

COLOPHON

Sources

How we know what’s on this page. References, not endorsements.

11sources

9primary records

9independently dated

Primary records

Proceedings of the National Academy of Sciences1998

Grandmothering, menopause, and the evolution of human life histories

The 1998 paper that formalized the grandmother hypothesis, with the human-versus-ape lifespan figures.

View source

Current Anthropology1997

Hadza Women's Time Allocation, Offspring Provisioning, and the Evolution of Long Postmenopausal Life Spans

Field data showing post-childbearing Hadza women foraged the most, over seven hours a day.

View source

Proceedings of the National Academy of Sciences2019

Postreproductive killer whale grandmothers improve the survival of their grandoffspring

Found grandcalf mortality risk rose about 4.5 times after a post-reproductive grandmother died.

View source

Wiley, Evolution1957

Pleiotropy, Natural Selection, and the Evolution of Senescence

George C. Williams's 1957 argument that menopause could be an adaptation rather than a flaw.

View source

PLOS Computational Biology2017

Grandmothering and cognitive resources are required for the emergence of menopause

A 2017 simulation supporting a role for cognition alongside grandmothering, finding no support for the mother hypothesis.

View source

Nature, Scientific Reports2018

Repeated evolution of post-reproductive lifespans in toothed whales

Identifies which toothed whales evolved menopause and shows it happened independently more than once.

View source

AARP2026

Grandparents Provide Billions in Unpaid Care of Grandkids

AARP's grandparents study on care rates, hours, and the combined value of grandparent support.

View source

Social Science & Medicine, via RePEc2017

A prospective study of associations among helping, health, and longevity

Berlin study linking grandparental caregiving to lower mortality, partly explained by health.

View source

American Presidency Project, UC Santa Barbara1978

Proclamation 4580, National Grandparents Day, 1978

Carter's 1978 proclamation creating the separate September grandparents observance.

View source

Additional coverage

Online Etymology Dictionary

nana

Traces "nana" to a child's word for grandmother first attested in 1844.

View source

Reader's Digest

Ways to Say Grandma and Grandpa in Different Languages

A list of grandmother terms worldwide, from Abuela and Oma to Halmoni and Obaachan.

View source

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