Zoology

This article focuses on the question of "why do chickens eat small stones?" It explains that chickens peck at sand and stones to grind up their food and aid digestion because they don't have teeth and need to swallow their food whole when eating. At the same time, it introduces the differences in digestion methods of birds with different diets. Birds that eat hard seeds rely on stones in their gizzards to grind up their food, while carnivorous birds rely on glands and bacteria to digest their food. Frugivorous birds usually don't have a distinct stomach and rely solely on a straight digestive tract to directly complete digestion and absorption.

This article focuses on the question of why birds don't have teeth, introducing the phenomenon that birds don't chew when eating, the structural characteristics of the beak, and the nature of the keratin "false teeth" in the beaks of some birds. It explains the evolutionary process of birds evolving from tooth-bearing reptiles and the gradual degeneration and disappearance of teeth, and explains the reasons why toothlessness can reduce the weight of the head to adapt to flight, meet the rapid feeding needs under high metabolism during flight, and evolve a specialized digestive system to match it.

The article focuses on the question of why pigeons don't get lost, introducing their remarkable homing ability and the history of humans using them to transmit information since ancient Rome. It explains three hypotheses about pigeon navigation that have been experimentally verified to varying degrees: solar navigation, geomagnetic navigation, and olfactory navigation. It also mentions that scientists at the University of Oxford have found that pigeons can guide their flights by remembering roads and landmarks along the route. The article points out that pigeons use multiple methods to return home, and more reasons for this behavior remain to be further discovered and verified.

This article focuses on the reasons why geese fly in a "V" formation, introduces the "energy-saving" hypothesis proposed by German aerodynamicist Karl Weisberg and the observation and verification of this hypothesis, mentions the controversy surrounding this hypothesis, and points out the obvious benefits of flying in a formation, which allows geese to observe their companions and adjust their flight state.

This article focuses on how geese know when to start migrating, introduces the timing rhythm of migratory birds' migration, the ancient people's observations on the correlation between migratory birds' migration and the change of seasons, and the guiding role of migratory birds in productive labor. It points out that food, temperature, and sunlight are external factors affecting migratory birds' migration. What really determines the migration time is the birds' internal biological clock, which has been regulated by the above factors for thousands of years. At the same time, it shows that there are risks if migratory birds migrate too early or too late, and it is very important to choose an appropriate migration time.

This article focuses on the question of why the dodo bird became extinct, introducing the physical characteristics, naming origin, and extinction situation of the dodo bird, a flightless bird once distributed on the island of Mauritius in the Indian Ocean. It points out that although hurricanes and floods may have been the causes of its extinction, most experts studying the dodo bird believe that overhunting by Europeans and the predation of their cats and dogs on the dodo's eggs and young birds were the main reasons for its extinction.

This article focuses on the question of why ostriches and penguins cannot fly. It points out that ostriches, penguins, and birds like the kiwi and emu all evolved into flightless birds between about 65 million and 34 million years ago, which is the result of birds' long-term adaptation to their environment. It also introduces the specific reasons why ostriches lost their ability to fly: adapting to the need to run for survival in the African grasslands and deserts, and the degeneration of their wings due to their massive body size; and why penguins lost their ability to fly: adapting to the need to dive and fish in cold environments, and their streamlined bodies storing fat and their wings degenerating into flippers.

This article focuses on the question of "why birds can fly", introducing the process of birds' origin from theropod dinosaurs in the Late Jurassic period 150 million years ago, and their gradual evolution of flight capabilities under the pressure of survival and natural selection. It also explains the reasons why birds can fly from three aspects: the aerodynamic structure of wings, physiological characteristics of weight reduction, and efficient energy supply systems. At the same time, it points out that the vast majority of existing birds can fly, while only a few birds cannot fly. Moreover, the flight capabilities and methods of different birds vary due to their adaptation to different environments.

This article takes the core question of why birds breed in spring as the starting point, explaining that food is the main factor determining the breeding time of birds. Most birds in temperate and high-latitude regions choose to breed at this time because of the abundance of food in spring, and it also introduces the differences in breeding time and frequency between birds of different regions and species.

This article answers the question of why hens can lay eggs continuously, introduces the concept and formation reasons of the number of eggs laid by wild birds, explains that birds lay eggs in two categories: fixed number and variable number. Domestic chickens are variable number egg-laying birds domesticated from red junglefowls. Under the condition of sufficient nutrition in artificial feeding, taking away the eggs laid by hens every day will induce them to keep laying eggs. At the same time, it introduces the different characteristics of the two types of egg-laying birds.

This article focuses on answering the question of "why hens can lay eggs without mating", introducing the background of domestic chickens being domesticated from wild chickens, explaining that the reproductive system of domestic hens does not atrophy and remains active for a long time due to their limited flying and abundant food supply, and that egg production is unrelated to mating. At the same time, it compares the characteristics of wild birds, whose reproductive systems only develop during the breeding season and rare cases of egg production without mating, and points out that the eggs we eat daily are mostly unfertilized eggs.

This article introduces the characteristics of three types of chicks, namely early-maturing, late-maturing, and semi-early-maturing chicks, by comparing the developmental differences of chicks from different bird species. It explains that baby ducks can move around independently shortly after birth because ducks belong to early-maturing birds, and the developmental types of different birds are the result of long-term adaptation to the environment and natural selection of species.