The Mammal Diversity Database 2.0, listing 6,759 mammal species and 50,230 species-level synonyms, unifies 267 yr of taxonomic, nomenclatural, and geograph

Cognitive scientists ascribe inferential processes to (neuro)cognitive systems to explain many of their capacities. Since these ascriptions have different

A vaccine to protect Australia's koalas against chlamydia has been approved for the first time, a development that scientists believe could stop the spread of the deadly disease that has ravaged populations of the beloved endangered animal.

A new major version of ggplot2 has been released on CRAN. Find out what is new here.

YouTube video by Dan Riskin

Territoriality is costly, and animals should adopt strategies to cope with these costs. Seasonal territoriality for breeding – a common strategy in many groups of animals – can reduce costs during th...

Flight may affect the dispersal and evolution of birds. Using a new evolutionary tree, Claramunt et al. find that efficient fliers have broader geographic ranges, and speciation reduces range size, bu...

Seeing sick-looking faces in virtual reality triggers brain circuit changes related to threat detection and boosts activity of certain immune cells.

Too often, nature is treated as a constraint to development. The prime minister’s comments earlier this year about the impact of bat conservation on the completion of HS2, sparked frustration within the conservation community, as this unhelpfully framed nature as being in conflict with economic growth.

The carotenoid-based colors of birds are a celebrated example of biological diversity and an important system for the study of evolution. Recently, a two-step mechanism, with the enzymes cytochrome P450 2J19 (CYP2J19) and 3-hydroxybutyrate dehydrogenase 1-like (BDH1L), was described for the biosynthesis of red ketocarotenoids from yellow dietary carotenoids in the retina and plumage of birds. A common assumption has been that all birds with ketocarotenoid-based plumage coloration used this CYP2J19/BDH1L mechanism to produce red feathers. We tested this assumption in house finches ( Haemorhous mexicanus ) by examining the catalytic function of the house finch homologs of these enzymes and tracking their expression in molting birds. We found that CYP2J19 and BDH1L did not catalyze the production of 3-hydroxy-echinenone (3-OH-echinenone), the primary red plumage pigment of house finches, when provided with common dietary carotenoid substrates. Moreover, gene expression analyses revealed little to no expression of CYP2J19 in liver tissue or growing feather follicles, the putative sites of pigment metabolism in molting house finches. Finally, although the hepatic mitochondria of house finches have high concentrations of 3-OH-echinenone, observations using fluorescent markers suggest that both CYP2J19 and BDH1L localize to the endomembrane system rather than the mitochondria. We propose that house finches and other birds that deposit 3-OH-echinenone as their primary red plumage pigment use an alternative enzymatic pathway to produce their characteristic red ketocarotenoid-based coloration. ### Competing Interest Statement The authors have declared no competing interest.

The carotenoid-based colours of birds are a celebrated example of biological diversity and an important system for the study of evolution. Recently, a two-step mechanism, with the enzymes cytochrome ...

Bats harbor diverse coronaviruses but temporal dynamics are less well studied. Here, the authors analyzed coronaviruses in Australian flying foxes over 3 years showing peak shedding and co-infections ...