Level 1 — Absolute Beginner

Bats are small animals that fly at night. They are not birds. They are mammals, like cats and people. Bats have fur and they feed their babies milk.

Scientists wanted to know where the first bats lived. For many years they thought the answer was Asia or Africa. A new study says something different.

The study says bats started in Europe. This was about 65 million years ago. That is just after the big dinosaurs died. Then bats moved to other parts of the world.

Scientists looked at the genes of 103 kinds of bats. They also looked at 44 old bones called fossils. The study was printed in a famous science magazine called Nature.

bat

A small flying animal that is active at night.

mammal

An animal with fur that feeds its babies milk.

fur

The soft hair that covers many animals.

scientist

A person who studies the natural world.

study

A careful piece of research.

fossil

The remains of an animal or plant preserved in rock.

gene

A tiny instruction inside a living thing that is passed to its children.

dinosaur

A very large animal that lived on Earth long ago.

Level 2 — Elementary

Where did bats come from? Scientists have argued about this for a long time, and most of them expected the answer to be Asia or Africa. A large new study published in Nature on 26 September says the answer is Europe.

The work was done by the Bat1K consortium, an international group of researchers. Among them were Ismael Galvan of the National Museum of Natural Sciences in Spain, Liliana Davalos of Stony Brook University, Michael Hiller of the Senckenberg Institute in Frankfurt, Emma Teeling of University College Dublin and David Ray of Texas Tech University.

The team read the complete genomes of 103 bat species. A genome is the full set of genetic instructions in a living thing. They then compared this genetic family tree with 44 fossils found in different parts of the world. Together the two kinds of evidence pointed to a European origin around 65 million years ago, shortly after the dinosaurs disappeared.

The study also changed the picture of how bats became bats. Flight and echolocation, the ability to find objects using sound, did not appear slowly over many millions of years. They developed early, close to the beginning of the group. From Europe the bats spread first into Africa, forming a Euro African core, and only later reached the other continents.

genome

The complete set of genetic instructions in a living thing.

species

A single kind of living thing that can breed with its own kind.

consortium

A group of organisations working together on one project.

researcher

A person who investigates a subject in detail.

evidence

Facts that support or disprove an idea.

origin

The place or moment where something began.

echolocation

Finding objects by sending out sounds and listening for the echo.

continent

One of the Earth's large land masses, such as Africa or Europe.

Level 3 — Intermediate

The origin of bats has been one of the more stubborn gaps in mammal evolution, partly because the animals themselves are poor candidates for fossilisation. Thin bones and membranous wings do not survive well, and the earliest known bats already look fully modern, which tells you the interesting part happened before the fossil record begins. A study published in Nature on 26 September addresses the gap from the other direction, and its conclusion is that bats arose in Europe roughly 65 million years ago rather than in Asia or Africa as had generally been assumed.

The work comes out of Bat1K, an international consortium whose contributors include Ismael Galvan of the National Museum of Natural Sciences in Madrid, Liliana Davalos of Stony Brook University, Michael Hiller of the Senckenberg Institute in Frankfurt, Emma Teeling of University College Dublin and David Ray of Texas Tech University, with additional participation from the University of Granada. Their method combined 103 complete bat genomes with the evidence from 44 fossils, using the genetic tree to establish the branching order and timing and the fossils to anchor that tree in real geography and real dates.

The timing is striking on its own. Sixty five million years places the origin of bats immediately after the extinction that ended the age of the large dinosaurs, in the ecological vacuum that followed. That is consistent with what is known about mammal diversification generally, but it puts bats among the early beneficiaries rather than late arrivals. From a European origin, the lineage expanded into Africa to form what the authors describe as a Euro African core, and only subsequently reached the remaining continents.

Two further results matter beyond biogeography. The first is that flight and echolocation appear near the base of the tree rather than accumulating gradually, which sharpens the question of how such demanding adaptations arose so quickly. The second is methodological: this is described as the first reconstructed genome of a flying mammal, and that reference sequence has uses well outside evolutionary biology. Bats are unusual in their longevity, their tolerance of viral infection and their resistance to certain diseases, and a properly resolved genomic framework is the starting point for asking why.

stubborn

Difficult to deal with or resolve.

membranous

Made of thin, soft sheets of tissue.

fossil record

The total collection of fossils that documents past life.

consortium

A partnership of institutions pursuing a shared project.

lineage

A line of descent from a common ancestor.

ecological vacuum

An environment left empty of competitors, open to new species.

diversification

The process of splitting into many different forms.

Level 4 — Advanced

The geographic origin of Chiroptera has resisted resolution for well over a century, and the reason is structural rather than a failure of effort. Bats are among the least tractable mammals for palaeontology: gracile skeletons, membranous flight surfaces and a preference for roosting habitats that rarely yield sediment all conspire against preservation. Worse, the oldest unambiguous bat fossils are already fully volant and echolocating, which means the morphological transition that would identify a homeland occurred entirely upstream of the available record. A study appearing in Nature on 26 September approaches the problem phylogenomically and concludes that the crown group originated in Europe approximately 65 million years ago, displacing the long favoured Asian and African hypotheses.

The analysis issues from the Bat1K consortium, whose contributing authors include Ismael Galvan at the Museo Nacional de Ciencias Naturales in Madrid, Liliana Davalos at Stony Brook, Michael Hiller at the Senckenberg Institute in Frankfurt, Emma Teeling at University College Dublin and David Ray at Texas Tech, with further input from the University of Granada. Its evidentiary architecture is the part worth attending to: 103 complete genomes establish topology and divergence timing, while 44 fossils supply the spatial and temporal calibration that molecular data cannot generate on its own. Neither line of evidence would be decisive alone, and the convergence of the two is what makes a European origin difficult to dismiss as an artefact of sampling.

The date is more than a detail. Placing the origin at roughly 65 million years locates it immediately after the end Cretaceous extinction, in the interval when surviving mammal lineages radiated into vacated niche space. Bats therefore emerge not as opportunistic latecomers but as one of the earlier products of that radiation, which has implications for how rapidly a vertebrate body plan can be reorganised. The authors further report that powered flight and laryngeal echolocation sit near the base of the tree rather than being distributed across successive branches, compressing the acquisition of two of the most demanding adaptations in vertebrate history into a narrow window. That is an uncomfortable result in the productive sense: it constrains the space of plausible mechanisms rather than merely adding a data point.

The instrumental value of the work may ultimately exceed its historical value. The paper is characterised as delivering the first reconstructed genome of a flying mammal, and a well resolved ancestral reference is precisely the substrate needed to interrogate the traits that make bats biomedically interesting. Their lifespans are anomalous for their body mass, their immune systems tolerate viral loads that would be lethal in comparable mammals, and their apparent resistance to certain cancers remains unexplained. Comparative genomics against a credible ancestral baseline converts those observations from curiosities into testable hypotheses about specific genes and regulatory regions. That the answer to a question about Eocene Europe should feed into human ageing and immunity research is a reminder that evolutionary biology is rarely only retrospective.