In human history, one in two children died prematurely, before becoming an adult. Today, one in twenty humans die before the age of 15. Somalia, where half of the population lives in extreme poverty, has the highest child mortality rate of one in seven. Non-human animals fare far worse. Almost all newborn animals die before reaching reproductive age. For wild birds, one in ten survives and is able to reproduce. That means nine out of ten die prematurely. For mammals (mostly rats) and farmed animals (mostly broiler chickens), only one in a hundred reaches adulthood. Amphibians (mostly frogs) and fish (mostly bristlemouths) have the highest premature mortality rates of all vertebrate animals: 999 out of 1000 newborns die before reaching adulthood. Humans are the only population where almost every child can become an adult and reproduce. How much suffering do wild and farmed animals experience when their premature mortality rates are so much higher than those of children living in extreme poverty?
Calculations
The most abundant wild bird species is the red-billed quelea. A female adult bird lays 3-4 eggs in a clutch, 2 clutches per year and has a lifespan of 2-3 years. That is about 20 offspring per couple. To avoid exponential population growth, only two offspring can survive and reproduce, for each adult couple. That means 9 out of 10 birds die.
The common wild mammal genus is the rat. Adult rats live 1-2 years and have on average 9 rats per litter with 10 litters per year. That is 100-200 offspring per couple, only two of them can survive.
Frogs are the most abundant order of amphibian. A frog spawn has 4000 eggs.
The most abundant fish genus (and also the most abundant vertebrate genus), is the bristlemouth. Many fish species lay more than 1000 eggs.
The most common farmed animal is the broiler chicken. On breeder farms, a chicken lays 150 eggs, almost all of them are raised as broilers and slaughtered prematurely at an age of 6 weeks.
Stijn Bruers, the rational ethicist 