Self‑destructive behavior among Hermann's tortoises on a Macedonian island is leading to 'demographic suicide'

Phys · May 10, 2026 · 1540 words · By Xavier Bonnet

Animal Behavior Population Dynamics Wildlife Conservation

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What to know about Animal Behavior

Researchers have observed a population of Hermann's tortoises on Golem Grad island in North Macedonia experiencing a severe sex-ratio imbalance. The study suggests that aggressive male behavior, including pushing females off cliffs, is creating a 'demographic suicide' loop that may lead to the population's extinction.

Propaganda risk 20%

Claims checked 15

Techniques found 2

Topics 3

Coverage spectrum

Coverage gap: Low Left coverage

Left0%

Center75%

Right25%

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

What happened

Self‑destructive behavior among Hermann's tortoises on a Macedonian island is leading to 'demographic suicide' Gaby Clark Scientific Editor Robert Egan Associate Editor On the strictly protected island of Golem Grad in North Macedonia, the tortoises are…

Why it matters

During prolonged courtship, aggressive males are exhausting the females and frequently pushing them off the cliffs.

Common ground

Consequently, there are now one hundred males for every female capable of laying eggs.

Perspective signals

The tension in the story is sharpened by Loaded Language, Exaggeration / Hyperbole: language that can make the dispute feel more urgent, personal, or adversarial than the underlying facts alone.

Follow-up questions

What new context would change how readers understand this Animal Behavior story?
What evidence would most clearly confirm or weaken the claim that On July 18 2023, a GPS device fitted with an accelerometer, attached to a female, recorded her fall of over 20 meters; she died, broken in two, along with her three eggs?
How does this story connect Animal Behavior with Population Dynamics over the next few days?

open_in_new Read the original article: https://phys.org/news/2026-05-selfdestructive-behavior-hermann-tortoises-macedon…

analyticsAnalysis

20%

Propaganda Score

confidence: 95%

Minor concerns. Some persuasive language detected, but largely factual.

psychologyPropaganda Techniques Detected

eFinder identified 2 propaganda techniques in this article. These signals explain how wording, emphasis, or missing context can shape a reader's interpretation.

warning

Loaded Language 80% confidence

Using words with strong emotional connotations to influence an audience.

Found in this article: eFinder flagged this technique because the story's framing or source language may guide readers toward a particular interpretation. Review the claim checks and evidence below to separate what is directly supported from what is implied by wording or emphasis.

Why it matters: Recognizing loaded language helps readers compare the article's framing with the underlying facts and with coverage from other sources.

warning

Exaggeration / Hyperbole 70% confidence

Overstating facts or claims to create a stronger emotional response.

Why it matters: Recognizing exaggeration / hyperbole helps readers compare the article's framing with the underlying facts and with coverage from other sources.

fact_checkClaims Checked

eFinder analyzed this article and checked 15 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

schedule Pending 5

check_circle Corroborated 4

help Insufficient Evidence 2

info Single Source 2

cancel Disputed 1

verified Verified 1

schedule

Claim 1: “On July 18 2023, a GPS device fitted with an accelerometer, attached to a female, recorded her fall of over 20 meters; she died, broken in two, along with her three eggs.”

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.

help

Claim 2: “the establishment of the field-monitoring program in 2008... this long-term monitoring program was awarded the CNRS's SEE-Life label in 2023.”

INSUFFICIENT EVIDENCE

No evidence was found in the provided search results regarding the 2008 monitoring program or the 2023 CNRS SEE-Life label.

info

Claim 3: “This is the only known example of demographic suicide in the wild to date.”

SINGLE SOURCE

The specific phrasing that this is the 'only known example of demographic suicide in the wild to date' appears in one specific source title/snippet, while other sources discuss the imbalance without confirming it is the 'only' such case globally.

menu_book

wikipedia NEUTRAL — A golem is an artificial animated being in medieval and Jewish folklore. Golem or The Golem may also refer to:
https://en.wikipedia.org/wiki/Golem_(disambiguation)

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wikipedia NEUTRAL — Golem Grad (Macedonian: Голем Град), meaning Big City/Town, also known as Snake Island or Pelican Island, is an island in North Macedonia. The island covers an area of more than 20 hectares. It is loc…
https://en.wikipedia.org/wiki/Golem_Grad

menu_book

wikipedia NEUTRAL — Grad (Cyrillic: град) is an Old Slavic word meaning "town", "city", "castle" or "fortified settlement". Initially present in all related languages as gord, it can still be found as grad, gradić, horod…
https://en.wikipedia.org/wiki/Grad_(toponymy)

+ 3 more evidence sources

check_circle

Claim 4: “On Golem Grad, the adults have no predators, as wild boars, dogs, rats and humans are absent from this strictly protected island.”

CORROBORATED

Sources confirm the island is uninhabited by humans and is a protected natural laboratory, though the specific list of absent animals (boars, dogs, rats) is partially corroborated by the general 'uninhabited' status.

travel_explore

web search NEUTRAL — The only island in landlocked Macedonia is uninhabited… at least by humans. Located in the south of Lake Prespa, near the Albanian border, Golem Grad is frequently referred to as “Snake Island.” Our e…
https://macedonia.for91days.com/golem-grad-better-known-as-s…

travel_explore

web search NEUTRAL — On Golem Grad island, at each capture and recapture event, researchers measure the individual’s body mass and size, note the exact location, note behaviour at capture, take additional morphological me…
https://www.pont.org/golem-grad-island-a-world-class-natural…

travel_explore

web search NEUTRAL — Golem Grad, the only natural island in the Republic of Macedonia, is located on Lake Prespa in the southwestern region of MacedoniaGolem Grad also commonly referred to as “Snake Island”, for the seaso…
https://journeymacedonia.com/scenic/golem-grad-snake-island/

cancel

Claim 5: “there are now one hundred males for every female capable of laying eggs.”

DISPUTED

The claim states a ratio of 100 males per female. However, multiple evidence sources report a ratio of 'up to 19 males to every female' or '19 to 1', which contradicts the 100:1 claim.

menu_book

wikipedia NEUTRAL — A golem is an artificial animated being in medieval and Jewish folklore. Golem or The Golem may also refer to:
https://en.wikipedia.org/wiki/Golem_(disambiguation)

menu_book

+ 3 more evidence sources

help

Claim 6: “On the plateau, over 700 adult males roam around looking for the forty or so adult females.”

INSUFFICIENT EVIDENCE

No evidence was found in the provided search results specifying the exact count of 700 males and 40 females.

check_circle

Claim 7: “On the strictly protected island of Golem Grad in North Macedonia, the tortoises are destroying their own population.”

CORROBORATED

Multiple independent web search results confirm that Hermann's tortoises on Golem Grad are experiencing a population decline due to self-destructive behavior and sex imbalance.

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wikipedia NEUTRAL — Over 22,500 species of wildlife have been recorded in North Macedonia. Over 10,000 of these are insects, which include 3,000 beetle species and large numbers of Lepidoptera, flies, and Hymenoptera. As…
https://en.wikipedia.org/wiki/Wildlife_of_North_Macedonia

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travel_explore

web search NEUTRAL — Golem Grad island in North Macedonia is full of Hermann’s tortoises. However, demographic projections suggest the last female could be wiped out by 2083.On the strictly protected island of Golem Grad …
https://theconversation.com/self-destructive-behaviour-among…

+ 2 more evidence sources

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Claim 8: “extraordinary population density, which stands at around 50 individuals per hectare—the highest ever recorded for tortoises.”

CORROBORATED

Two separate web search snippets explicitly state the population density is around 50 individuals per hectare and that this is the highest ever recorded for tortoises.

travel_explore

web search NEUTRAL — Golem Grad (Macedonian: Голем Град), meaning Big City/Town, also known as Snake Island or Pelican Island, is an island in North Macedonia. The island covers an area of more than 20 hectares. [1]
https://en.wikipedia.org/wiki/Golem_Grad

travel_explore

web search NEUTRAL — All these factors explain the extraordinary population density, which stands at around 50 individuals per hectare—the highest ever recorded for tortoises.
https://phys.org/news/2026-05-selfdestructive-behavior-herma…

travel_explore

web search NEUTRAL — All these factors explain the extraordinary population density, which stands at around 50 individuals per hectare - the highest ever recorded for tortoises.
https://theconversation.com/self-destructive-behaviour-among…

schedule

Claim 9: “Of the females that died, 22% suffered a fatal fall, compared to 7% of the males.”

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.

verified

Claim 10: “Hermann's tortoises (Testudo hermanni boettgeri) thrive on the wooded plateau [of Golem Grad].”

VERIFIED

Web results confirm that Testudo hermanni boettgeri is a recognized subspecies and that Golem Grad is inhabited by Hermann's tortoises.

travel_explore

web search NEUTRAL — Testudo hermanni boettgeri, Mojsisovics 1889. [Bearbeiten | Quelltext bearbeiten]. Der Rückenpanzer von T. h. boettgeri ist etwas weniger hochgewölbt als bei der westlichen Unterart.
https://de.wikipedia.org/wiki/Griechische_Landschildkröte

travel_explore

web search NEUTRAL — Biotype, nomenclature and taxonomic diagnostic characters of Testudo hermanni hermanni GMELIN 1789 in Southern France with preliminary notes on comparative egg morphology with T. h. boettgeri MOJSISOV…
https://www.tortoisetrust.org/articles/biohermanni.html

travel_explore

web search NEUTRAL — Hermann’s tortoise (Testudo hermanni) is listed as “Near threatened” in the IUCN Red list of endangered species.The high number of islands with introduced individuals is associated with the tendency o…
https://herpetozoa.pensoft.net/article/103510/list/18

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Claim 11: “aggressive males are exhausting the females and frequently pushing them off the cliffs.”

CORROBORATED

Multiple sources explicitly state that aggressive males exhaust females and push them off cliffs during courtship.

menu_book

travel_explore

web search NEUTRAL — Golem Grad is home to around 1000 Hermann's tortoises, which were introduced by humans to the island. Due to genetic variation or an initial imbalance in sex when they were first introduced, the torto…
https://en.wikipedia.org/wiki/Golem_Grad

travel_explore

web search NEUTRAL — Golem Grad island in North Macedonia is full of Hermann’s tortoises. However, demographic projections suggest the last female could be wiped out by 2083.During prolonged courtship, aggressive males ar…
https://theconversation.com/self-destructive-behaviour-among…

+ 1 more evidence source

schedule

Claim 12: “it takes a female around fifteen years to reach adulthood.”

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.

schedule

Claim 13: “In 2009, we captured 45 adult females in the field, compared to 37 in 2010, 20 in 2024, and just 15 in 2025.”

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 14: “The mild Mediterranean climate of this lake, situated at an altitude of 850 meters, is also favorable for reptiles.”

SINGLE SOURCE

The provided evidence for this claim contains generic definitions of lakes and does not mention the altitude of Lake Prespa or its climate.

travel_explore

web search NEUTRAL — Lake Idro, an Italian prealpine lake of glacial origin situated largely within the province of Brescia (Lombardy) and in part in Trentino. Sunset over Lake Michigan at Nordhouse Dunes in Manistee Nati…
https://en.wikipedia.org/wiki/Lake

travel_explore

web search NEUTRAL — Apr 1, 2026 · What is a lake? Learn the clear definition, how lakes form, how they differ from ponds and reservoirs, and why lakes matter in geography.
https://geographypin.com/what-is-a-lake/

travel_explore

web search NEUTRAL — View maps of Lake Serene and the surrounding area, including the location of public access sites. Summary of Lake Serene health and recreational opportunities.
https://snohomishcountywa.gov/5388/Serene

schedule

Claim 15: “The oldest males are over 60 years old and the oldest female is 35.”

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 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.