Latest news with #mammals
The Independent
a day ago
- Science
- The Independent
Why our chins remain an evolutionary mystery
Scientists are still trying to understand the evolutionary reasons behind unique human features, such as the chin and the relative size of testicles. The concept of convergent evolution, where a feature evolves multiple times independently, serves as a natural experiment to determine the purpose of body parts. Analysis of testicle size across various mammals, including monkeys, gorillas, chimps, and dolphins, reveals a consistent correlation between larger testicles and promiscuous mating behaviors. This correlation suggests that larger testicles evolved to facilitate sperm competition in species with multiple partners, with human testicle size falling in the middle. The human chin remains an evolutionary mystery because its uniqueness among mammals, including Neanderthals, prevents the use of convergent evolution to test hypotheses about its purpose.
Health Line
12-06-2025
- Health
- Health Line
Why Fleas Live on Pets and Not Humans
Fleas can bite humans, but they live and reproduce on animals, under the protection of fur and feathers. To get rid of fleas, you need to treat your pet and your home. When you think of fleas, you probably associate them with your pet. Fleas generally live on dogs, cats, birds, or other warm-blooded animals, because their fur and feathers make it easy to hide and reproduce. Fleas are very small, wingless parasites that bite skin and suck blood to survive. While fleas don't typically live on human bodies, they can still bite you. A flea can jump up to 13 inches, so it's possible a pet or other animal can transfer them to you. This article looks at where fleas prefer to live, how long they live, and how to get rid of them. Can fleas live on humans as well as pets? Fleas do not live on humans, but they can still bite us. In the United States, the most common fleas are cat fleas. These can live on both cats and dogs. There are also dog fleas, but they are less common in the United States. Fleas can also live on other mammals and birds, such as rodents and livestock. There are 2,500 different types of fleas around the world. Fleas are attracted to animals because of their fur or feathers. They can burrow into fluffy bodies to hide and feed. They then lay eggs that eventually hatch after the larva and pupa stages. This cycle can cause a flea infestation on your pet (or livestock) that will need to be treated. Fleas do not live on humans because they lack substantial hair like animals, and it's very difficult to reproduce without the protection of fur or feathers. Can humans get fleas in their hair? Fleas do not live on humans, but they may jump on your hair if you're sleeping with a pet or bending down to pet them. Generally, though, flea bites occur near the feet, ankles, and legs by jumping from an infested pet or an item in your home. Fleas can live in carpets, fabric-covered furniture (like sofas), and pet beds. How long can fleas live on humans? It is very unlikely that a flea will stay on your body for any substantial amount of time. Humans do not have fur or feathers like other animals and birds. Fur and feathers give fleas a safe place to lay eggs and repopulate without being noticed. If a flea lands on you, you're likely to wash or scratch it off before it can breed. Can humans carry fleas from one home to another? It's rare that a flea will transfer from one body to another. It's more likely that an animal or person will get fleas from areas where animals live and sleep. It's possible that bringing an infested pet bed into a new home could spread fleas to another source. Do fleas bite humans? Fleas can bite people, most often on the feet, ankles, and legs. They may bite three times in a row. This is known as 'breakfast, lunch, and dinner.' Typically, the initial bites do not cause a lesion in the skin, but once an individual is exposed to the fleas for a longer period of time, they may develop a hypersensitive reaction. The red marks from a flea bite may last a few days, but they may get worse if you are more sensitive to the bites or if the area becomes infected. The photo below shows what flea bites on a person with white skin look like. Do fleas pose any other dangers to people or pets? Fleas are more than a nuisance. They can actually cause several serious conditions and may be fatal to animals if the infestation is so severe that it interferes with their overall health. Fleaborne diseases Fleas can carry several different diseases that may be transmitted during a bite. In the United States, the most common include: plague (in Western states) typhus (in Southern states) cat scratch fever (also called cat scratch disease) parasites (such as tapeworms) These diseases, whose incidence rates appear to be increasing due to the effects of climate change, require medical treatment, such as antibiotics or antiparasitic medications. Allergic reactions A flea bite may cause an allergic reaction on your skin because your body reacts strongly to the flea's saliva. An allergic reaction to the bite can cause flea allergy dermatitis. This can result in: irritated, red skin extreme itchiness hives infection Allergic reactions to flea bites can also occur in animals. An allergic reaction can cause an animal to scratch their bites to such an extent that their skin becomes raw or they lose hair. In these cases, you'll need to take your pet to a vet for diagnosis and treatment. How to get rid of a flea infestation If you suspect a flea infestation, you will need to treat both your pet and your home. There are several methods you can try to remove fleas. To remove fleas from your pet Talk to a veterinarian about the safest and most effective method for flea removal. Use a flea comb when grooming your pet. Leave soap on your pet for at least 5 or 10 minutes when giving them a bath. Use a veterinarian-prescribed flea medication that kills fleas. Follow the instructions very closely for over-the-counter flea products. Protect your pet by avoiding the application of flea removal in their eyes, nose, and mouth. Use gloves and other protective gear on yourself when applying flea removal products. To remove fleas from inside or outside your home Wash pet beds and other fabric toys or mats in hot water. Vacuum thoroughly, then transfer the vacuumed debris to a plastic bag, seal it, and dispose of it outside immediately. Apply insecticides to baseboards, but make sure the insecticides you're using are not harmful to pets. Clean all upholstery (furniture, rugs, carpet, bedding window treatments) often. Close up holes where wild animals may get into or near your house. Remove debris surrounding your house. Call a pest control service if you suspect you have a serious infestation of fleas. Preventing a flea infestation in your home You can avoid a flea infestation in your home in several ways, including: checking your pet regularly for fleas cleaning your pet's sleeping areas preventing your pet from entering spaces likely to have fleas from other animals, like crawl spaces or barns The most common reason veterinarians see pets with fleas is that owners stop giving their pets quality flea and tick prevention during the cold, winter months. Fleas can survive off an animal's body in the summer, but have to be on a body in the winter to survive. That's why it's important to provide year-round monthly flea prevention to your pet to prevent infestations. Takeaway Fleas can bite humans, but they prefer to live on animals that offer the protection of fur and feathers. Fleas can also live in the sleeping spaces of your pets, such as beds, carpets, and sofas. Flea bites are irritating and may also cause a more serious health condition that requires a doctor's treatment.
The Guardian
10-06-2025
- Science
- The Guardian
Distorted moles to lesser bilbies: a new way to marvel at Australia's supremely weird and unique mammals
The skeleton of Australia's supremely weird southern marsupial mole has a distorted skull 'that looks like a god rammed it into a mountain side on its day of creation', says Vera Weisbecker. It is one of 189 Australian mammals in a new public database of 3D scans of bones and skeletons where users can spin the mole's skeleton around, zooming in and out, to marvel at its oddness. 'It's my favourite because that skeleton is a one-stop shop that dispels the myth that our animals are primitive – it's like the essence of mammal design in so many ways, with these claws like shovels so they can almost swim through the sand,' Weisbecker says. Weisbecker, an associate professor at Flinders University in South Australia, is a self-confessed 'militant' out to dispel what she says is a common scientific myth that Australia's marsupial mammals are less evolved. Sign up to get climate and environment editor Adam Morton's Clear Air column as a free newsletter To help in her mission, she has led the creation of Ozboneviz – a virtual collection of 1,600 bones and skeletons for researchers, teachers, students, artists and anyone else who wants to gaze at mandibles, femurs or the skeletons of ringtail possums or brush-tailed phascogales. 'Australia leads the world in mammal extinctions, but we are losing far more than a few fluffy rat-like critters,' she says. 'Our mammals have evolved in isolation for nearly 40m years – there is simply nothing like them anywhere else. They're all so weird and diverse.' As a German native, she says many scientists in the northern hemisphere with a western scientific background see even the common kangaroo as exotic. Australia's marsupials, to them, are 'an alternative universe'. To create Ozboneviz, researchers spent three years travelling around Australian museums and universities digitising specimens using a 3D light scanner. Some complete specimens were put into CT scanners so the whole skeleton could be digitised – such as the ringtail possum, the rakali (a native water rat), the golden bandicoot and the northern quoll. But there are also more individual mandibles, skulls, femurs and ankle bones in the collection than you can shake a tibia-shaped stick at. The technical detail in the collection means the online specimens can be used to help researchers identify bones found in the field. Sign up to Clear Air Australia Adam Morton brings you incisive analysis about the politics and impact of the climate crisis after newsletter promotion 'Hopefully this will lead the way to an even wider use of digitisation to make Australia's unique local biodiversity accessible to the global public,' Weisbecker says. Ten extinct species have also been digitised, including the full skeleton of the lesser bilby and the skull of the thylacine, also known as the Tasmanian tiger that some scientists are trying to revive. The 3D files are housed in a repository called MorphoSource, but some of the more important and intriguing specimens have been uploaded to a site allowing users to spin and zoom the 3D images. 'This means the public can compare the cranium of a fox to a thylacine and dingo, for example, and compare the size and shape of limb bones of common marsupials,' says the Flinders University archaeologist Dr Erin Mein, of the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage. The project is described in an article in the scientific journal Bioscience.
Times
15-05-2025
- Science
- Times
Eight out of ten ginger cats are male. Now we finally know why
Marmalade-coloured cats are not the only orange-furred mammals in the animal kingdom, but scientists have discovered something that sets the tabbies apart from tigers, orangutans and even redheaded humans. Only in domestic cats is the colour orange strongly linked to one sex, with males making up at least 80 per cent of ginger felines. Researchers have now not only uncovered the gene responsible, but also the process that causes it to be linked so strongly to males. • Cats become Britain's favourite pet as Gen Z copy Taylor Swift A gene known as Arhgap36 is shared by many mammalian species, including humans, but it normally has no link to pigmentation. Instead, it helps to govern the relationship between the nervous and hormonal systems. Cancers have
South China Morning Post
11-05-2025
- Science
- South China Morning Post
China's dinosaur discovery reveals ancient food chain secrets
A fossil discovery in China shows a complex prehistoric food chain from 125 million years ago. The fossilised remains of Huadanosaurus sinensis – a newly identified compsognathid-like theropod dinosaur – were found in Liaoning province. Scientists discovered two small mammals inside the dinosaur's stomach. One was an eutherian, a distant relative of modern mammals. The second was a gobiconodontid, a group that includes the Repenomamus – a mammal about the size of a badger. The eutherian in its stomach was swallowed whole, suggesting Huadanosaurus likely killed its prey with a powerful bite. This has changed what scientists know about the animals. Earlier fossils showed Repenomamus ate vertebrates. This previous fossil finding and the new study suggest that dinosaurs and mammals in the region may have formed a food web in which they were both predator and prey to each other. Answer: Scientists found the remains of two small mammals, suggesting there was a complicated food web
