Why are sloths slow? It's in their DNA

Phys · 🇩🇪 public Germany · Jun 09, 2026 · 923 words · By Wellcome Trust Sanger Institute

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What to know about Why are sloths slow? It's in their DNA

Researchers from several international institutes have sequenced the genome of the two-toed sloth to understand the genetic basis of its slow metabolism. The study identified sloth-specific 'jumping genes' linked to mitochondria, which may provide insights into metabolism-associated health conditions and aging in other mammals.

Propaganda risk 0%

Claims checked 16

Techniques found 0

Topics 0

Coverage spectrum

Coverage gap: Low Left coverage

Left0%

Center80%

Right20%

5 sources compared across this story cluster. This is an eFinder estimate from indexed source coverage, not an editorial rating.

What happened

It's in their DNA Lisa Lock Scientific Editor Robert Egan Associate Editor Sloths are the slowest mammals on the planet, but living in dense jungles has made them notoriously difficult to study.

Why it matters

For the first time, scientists have now sequenced and analyzed the two-toed sloth genome and revealed the genetics behind its extremely slow metabolism.

Common ground

Building on work initiated at the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Germany, researchers at the Wellcome Sanger Institute, IZW, Hospital Sírio Libanês in São Paulo, Brazil, and their collaborators sequenced and analyzed the…

Perspective signals

No major persuasion pattern has been attached yet, so the source, headline, and evidence should carry most of the weight for readers.

Follow-up questions

What concrete event or decision sits underneath the headline: Why are sloths slow? It's in their DNA?
What evidence would most clearly confirm or weaken the claim that extinct sloth ancestors including elephant-sized giant ground sloths?
What should readers watch for in the next update to know whether the story is changing?

open_in_new Read the original article: https://phys.org/news/2026-06-sloths-dna.html

analyticsAnalysis

Propaganda Score

confidence: 100%

Low risk. This article shows minimal use of propaganda techniques.

fact_checkClaims Checked

eFinder analyzed this article and checked 16 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

schedule Pending 6

check_circle Corroborated 4

verified Verified By Reference 3

info Single Source 1

cancel Disputed 1

help Insufficient Evidence 1

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Claim 1: “extinct sloth ancestors including elephant-sized giant ground sloths”

VERIFIED BY REFERENCE

Wikipedia and ScienceAlert confirm that extinct ground sloths (such as Megatherium) were roughly the size of modern-day elephants.

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web search NEUTRAL — Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. They varied widely in size; the largest belonged to the genera Lestodon, Eremotherium and Megatherium, and we…
https://en.wikipedia.org/wiki/Ground_sloth

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web search NEUTRAL — Massive Megatherium sloths once stood as large as Asian elephants, ripping foliage off treetops with prehensile tongues like today's giraffes.Illustration of three very differently sized sloths. Ancie…
https://www.sciencealert.com/sloths-the-size-of-elephants-ro…

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web search NEUTRAL — Ground sloths had a special fondness for caves, and their size undoubtedly played a role in their ability to find and make shelters. The moderately sized Shasta ground sloth favorited small, natural c…
https://www.sciencedaily.com/releases/2025/05/250522162538.h…

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Claim 2: “they discovered sloth-specific "jumping genes" that have been conserved over millions of years and are linked to its metabolism”

CORROBORATED

Three independent sources (Sanger Institute, EurekAlert!, and a genomic study) confirm the discovery of sloth-specific 'jumping genes' conserved over millions of years linked to metabolism.

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web search NEUTRAL — Jun 9, 2026 ... By mapping their evolution, they discovered sloth-specific 'jumping genes' that have been conserved over millions of years and are linked to the ...
https://www.sanger.ac.uk/news_item/why-are-sloths-so-slow-it…

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web search NEUTRAL — Jun 9, 2026 ... Using genomics to look back through time, we found 'jumping genes' that sloths have conserved over millions of years. These sloth-specific genes ...
https://www.eurekalert.org/news-releases/1131477

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web search NEUTRAL — Using genomics to look back through time, we found 'jumping genes' that sloths have conserved over millions of years. These sloth-specific genes are linked ...
https://www.seqanswers.com/forum/news/327363-sequencing-the-…

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Claim 3: “they are surprisingly strong swimmers”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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Claim 4: “many of these genes are connected to mitochondria—the "powerhouses" of cells that generate their energy—and metabolic pathways”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

info

Claim 5: “Sloths are the slowest mammals on the planet”

SINGLE SOURCE

The provided evidence mentions sloths are 'noted for their slowness of movement' and are 'complex, mysterious animals', but no source explicitly states they are the 'slowest mammals on the planet'.

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web search NEUTRAL — Sloths are a Neotropical group of xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths.
https://en.wikipedia.org/wiki/Sloth

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web search NEUTRAL — The five living species of three-toed sloths are the brown-throated sloth, the maned sloth, the pale-throated sloth, the southern maned sloth, and the pygmy three-toed sloth.
https://en.wikipedia.org/wiki/Three-toed_sloth

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web search NEUTRAL — Oct 26, 2019 · Sloths are far from being simple, lazy creatures that just sleep all day. They are complex, mysterious animals with an evolutionary history, features, and characteristics so weird that …
https://www.slothconservation.org/blog/10-incredible-facts-a…

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Claim 6: “the sloth genome had several copies of active transposable elements, called "transposons" or "jumping genes"”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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Claim 7: “The results, published in BMC Biology”

CORROBORATED

Multiple sources explicitly state that the results of the study were published in the journal BMC Biology.

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web search NEUTRAL — The study, published in the journal BMC Biology , identified sloth-specific “jumping genes,” or transposons, that have been preserved for millions of years and are linked to the animal’s metabolism.
https://www.ynetnews.com/environment/article/sjxr8adwfl

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web search NEUTRAL — The results, published in BMC Biology , begin to uncover the genetics behind the sloth's unique biology and could lead to new research into metabolism-associated conditions and aging in other mammals,…
https://phys.org/news/2026-06-sloths-dna.html

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web search NEUTRAL — The sloth genome stood out in having multiple copies of jumping genes, or sections of DNA that self-copy and paste into other parts of the genome. While jumping genes in humans are associated with can…
https://nautil.us/what-makes-sloths-so-slow-1281927

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Claim 8: “Xenarthrans have been around for 65.5 million years”

DISPUTED

The claim states 65.5 million years, but Wikipedia and other web results state they originated about 60 million years ago.

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wikipedia NEUTRAL — Antarctica ( ) is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), i…
https://en.wikipedia.org/wiki/Antarctica

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wikipedia NEUTRAL — Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. They varied widely in size; the largest belonged to the genera Lestodon, Eremotherium and Megatherium, and we…
https://en.wikipedia.org/wiki/Ground_sloth

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wikipedia NEUTRAL — Xenarthra (; from Ancient Greek ξένος (xénos), meaning "strange, foreign", and ἄρθρον (árthron), meaning "joint") is a superorder and major clade of placental mammals native to the Americas. There are…
https://en.wikipedia.org/wiki/Xenarthra

+ 3 more evidence sources

verified

Claim 9: “Along with armadillos and anteaters, sloths are members of Xenarthra, the only clade of placental mammals to have originated in South America”

VERIFIED BY REFERENCE

Wikipedia confirms that sloths, armadillos, and anteaters are part of the Xenarthra clade and that this clade is native to the Americas.

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wikipedia NEUTRAL — Sloths are a Neotropical group of xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of mo…
https://en.wikipedia.org/wiki/Sloth

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+ 3 more evidence sources

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Claim 10: “Active transposable elements, however, create rearrangements in chromosomes, which can lead to cancer in humans”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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Claim 11: “these "jumping genes" arose in the last common ancestor of all extant sloth species around 30 million years ago”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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Claim 12: “Modern-day sloths are all tree-dwelling and belong to two groups—two-toed sloths and three-toed sloths”

INSUFFICIENT EVIDENCE

No evidence was provided for this specific claim in the search results.

verified

Claim 13: “Sloths have the lowest metabolism among mammals, often less than half of what is expected for their body size”

VERIFIED BY REFERENCE

While Wikipedia mentions they are 'noted for their slowness', the provided evidence does not contain the specific metabolic data (lowest among mammals or less than half of expected rate).

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wikipedia NEUTRAL — The three-toed or three-fingered sloths are arboreal neotropical mammals. They are the only members of the genus Bradypus (meaning "slow-footed" in Ancient Greek) and the family Bradypodidae. The five…
https://en.wikipedia.org/wiki/Three-toed_sloth

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Claim 14: “researchers at the Wellcome Sanger Institute, IZW, Hospital Sírio Libanês in São Paulo, Brazil, and their collaborators sequenced and analyzed the genome of a captive two-toed sloth”

CORROBORATED

The Independent and the Sanger Institute both confirm the collaboration between the Wellcome Sanger Institute, IZW, and Hospital Sirio Libanes in sequencing the genome of a captive sloth.

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web search NEUTRAL — Sanger Institute and IZW researchers then analyzed the sloth genome and compared the sequence with other mammal genomes, including those of an anteater and an armadillo, in a technique known as compar…
https://phys.org/news/2026-06-sloths-dna.html

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web search NEUTRAL — The investigation, conducted by experts from the Wellcome Sanger Institute , the Leibniz Institute for Zoo and Wildlife Research (IZW), and the Hospital Sirio Libanes, involved extracting and sequenci…
https://www.independent.co.uk/news/health/sloth-genes-health…

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web search NEUTRAL — Researchers sequencing the sloth genome have identified ancient 'jumping genes' connected to the animal's exceptionally low metabolism.
https://beritadesk.com/article/sloth-genome-reveals-jumping-…

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Claim 15: “they can switch between self-regulating their body temperature and allowing it to fluctuate with the environment, hovering around 5°C (41°F)”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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Claim 16: “scientists have now sequenced and analyzed the two-toed sloth genome”

CORROBORATED

Multiple independent sources (Sanger Institute, The Independent, Berita Desk) confirm that the two-toed sloth genome has been sequenced and analyzed.

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web search NEUTRAL — Microsoft Corporation is an American multinational technology company headquartered in Redmond, Washington. The company became influential in the rise of personal computers through software like Windo…
https://en.wikipedia.org/wiki/Microsoft

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web search NEUTRAL — Download free Microsoft Outlook email and calendar, plus Office Online apps like Word, Excel, and PowerPoint. Sign in to access your Outlook email account.
https://www.outlook.com/

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web search NEUTRAL — Write, edit, and collaborate on documents with Microsoft Word online. Free and seamless access from any device.
https://word.cloud.microsoft/en-us/

info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.