The Animal Kingdom Today

1. Selected wild carnivoran populations

Seals account for four of the five entries in this selected comparison of wild members of the order Carnivora. The crabeater seal’s broad circumpolar estimate is especially large, while the harp seal figure describes a specific North Atlantic stock. The American black bear introduces a terrestrial example, with the plotted value representing the midpoint of a published North American range. A shared taxonomic order does not mean these animals occupy similar habitats or obtain food in the same way.

The bars are useful for comparing scale, but their geographic coverage and dates differ. The northern fur seal value refers only to the Eastern Pacific stock, whereas the southern elephant seal overview covers the Southern Ocean. These are therefore selected published estimates rather than a global league table. The cited sources identify the geographic scope and available uncertainty bounds for each estimate. Changes in survey methods, coverage and models can revise an estimate even when the underlying animal population has not changed by the same amount.

Sources: Australian Antarctic Program (crabeater seal); DFO (2024 Northwest Atlantic harp seal estimate); International Association for Bear Research and Management (black bear); Antarctic Environments Portal (southern elephant seal); NOAA 2024 stock assessment (Eastern Pacific northern fur seal). Links appear in Sources. Values shown in millions; American black bear uses the midpoint of 850,000–950,000.

2. Elephant population estimates: different surveys and periods

African savanna elephants have the largest published count in this comparison, followed by African forest elephants and Asian elephants. The savanna figure comes from the Great Elephant Census, whose aerial surveys covered selected areas across eighteen countries in 2014–2015. It should not be mistaken for a complete count of every savanna elephant in Africa. The other two bars draw on different reporting periods and estimation approaches.

Forest elephants illustrate how difficult wildlife counting can be. Dense habitat limits direct observation, and the later assessment incorporated methods including DNA evidence. Its central estimate is accompanied by a 95% confidence interval of 99,343–172,297 animals. Better detection can increase the number estimated without demonstrating biological recovery. These three figures are shown as separate bars because adding them into a single pie would imply a shared global census that does not exist here. Their strongest message is the contrast in scale alongside the importance of knowing where, when and how each estimate was made.

Sources: African savanna elephant, African forest elephant, Asian elephant. These figures are not contemporaneous global totals.

3. Taxonomic subdivisions of selected large cats

The leopard has the greatest number of recognised subspecies within this selected group under the Cat Specialist Group’s 2017 framework. The cheetah follows, while the tiger, lion and cougar are each divided into two subspecies. Jaguar and snow leopard are treated as monotypic in that framework, meaning they are not divided into recognised subspecies. Each is represented by one undivided species unit so that its presence remains visible in the chart.

Taxonomy describes how scientists classify biological variation; it is not a ranking of abundance, ecological importance or evolutionary success. A species with more named subspecies does not necessarily have more animals or greater measured genetic diversity. Classification can also change when new genetic, anatomical and geographic evidence becomes available. The framework used here is identified explicitly because the specialist group is reviewing cat classification. Using one consistent reference avoids combining older regional names with newer classifications, a mixture that can produce misleading comparisons even when each name has appeared in a publication.

Source: IUCN Cat Specialist Group, 2017 classification. One unit denotes a monotypic species; other values count recognised subspecies.

4. Selected great-ape population estimates and thresholds

Fishes contribute the largest number of assessed species and the largest absolute number classified as threatened among these five vertebrate groups. Amphibians have fewer assessed species than birds or reptiles, yet their threatened total is substantially larger than either. The stacked bars make both the size of the assessed pool and the threatened component visible, helping distinguish a large count from a large proportion.

Red represents species classified as Vulnerable, Endangered or Critically Endangered in the 2025-1 Red List release. The grey remainder includes all other assessed categories, including Data Deficient and extinct species; it should not be interpreted as a block of species known to be safe. Assessment coverage also varies between groups. A group with many unassessed species cannot be assumed to have the same risk profile as those already evaluated. Chart 10 expresses these same data as percentages, allowing a complementary comparison alongside the absolute numbers retained here.

Source: IUCN Red List 2025-1, Table 1b. Other assessed categories do not mean “safe”.

6. Relative brain size in selected mammals

Encephalization quotient, usually shortened to EQ, compares an animal’s brain size with an expected value based on body size. The selected dolphins have higher values than the primates in this particular published comparison. That pattern describes relative brain size under a mathematical reference model. It does not mean that the animals have been given an intelligence test, nor that their cognitive abilities can be arranged in a simple universal order.

A useful comparison needs consistent measurements and definitions. These values therefore come from one published table rather than mixing figures calculated under different conventions. Even then, body mass, sampling and the reference relationship influence the result. Behaviour, sensory specialisation and the organisation of neural tissue are not captured by one ratio. The related scatter plot in chart 8 separates brain mass from body mass so that readers can see why absolute and relative size answer different questions. Both visualisations use the same eight animals and the same published measurements.

Source: Cairó (2011), Table 1, selected non-human mammal measurements. EQ is a relative-size index, not an IQ score.

7. Selected vertebrate longevity records and estimates

The Greenland shark stands well above the other selected vertebrates, with a central age estimate approaching four centuries. Bowhead whales and rougheye rockfish also exceed two hundred years in the database used here. The comparison includes both fishes and reptiles alongside a mammal, showing that exceptional longevity occurs in several very different animal lineages. The figures describe selected maximum records or estimates, not the lifespan that a typical individual should be expected to reach.

Evidence quality and recording conditions matter. Some entries come from wild animals whose ages were estimated, while others describe individuals maintained in captivity. The animal table identifies whether each lifespan record comes from a wild or captive animal. All values are taken from the same AnAge release, which makes the comparison reproducible but does not claim to include every subsequently reported record. Particularly striking claims need supporting evidence: a long-lived individual, an uncertain age estimate and an average life expectancy are three distinct quantities. The shark photograph below explains the estimation behind the largest bar.

Source: AnAge, build 15 (2023), João Pedro de Magalhães / HAGR; CC BY 3.0 data terms. Greenland shark: Nielsen et al. (2016).

8. Brain mass versus body mass in selected mammals

A scatter plot reveals information that is hidden when animals are arranged only by a single index. Each point combines body mass on the horizontal axis with brain mass on the vertical axis. The bottlenose dolphin and western gorilla have similar body masses in this dataset, but their reported brain masses differ considerably. The northern right whale dolphin also has a relatively large brain within the range of animals shown.

The smaller primates cluster toward the lower-left corner because both their bodies and brains are lighter. Their positions do not imply a corresponding ranking of learning ability or behavioural complexity. The chart is deliberately limited to the same eight non-human mammals used in the EQ comparison, making it possible to move between raw measurements and the derived index. A wider selection could change the apparent relationship substantially. No fitted trend line is added to this small, selected sample, and the chart should not be used to infer how brain mass scales across all mammals.

Source: Cairó (2011), Table 1. Same selected measurements as chart 6; body mass in kg and brain mass in g.

9. Global mammal biomass by broad group

Domesticated mammals and humans account for most of the mammal biomass in this rounded global comparison. Wild marine mammals contribute a smaller share, and wild land mammals a smaller share again. The result differs sharply from a species-count chart: one very numerous, heavy species can contribute more mass than many small species combined. Biomass therefore offers a distinct view of humanity’s relationship with the rest of the mammal world.

The units are millions of tonnes of wet mass, so the segments represent weight rather than numbers of individuals, occupied habitat or ecological value. Domesticated mammals include animals maintained by people, including livestock and pets. The study’s estimates also carry uncertainty, especially for wild animals that are difficult to count. Rounded values make the broad contrast readable without suggesting exact precision. The green and blue-green segments distinguish terrestrial and marine wildlife, while the warm domesticated segment separates that human-managed group. These proportions apply to mammals only, not to all animals or all life.

Source: Greenspoon et al. (2023), The global biomass of wild mammals. Rounded wet-mass estimates; chart totals 1,080 million tonnes.

10. Threatened share of assessed vertebrates

Amphibians move to the top when threatened species are expressed as a share of all species assessed in each group. Mammals follow, while fishes have a smaller percentage despite the larger threatened count shown earlier. This reversal illustrates why totals and proportions should be viewed together. A large assessed pool can produce a large threatened count even when the fraction affected is lower.

Every bar has the same length, with red showing the threatened share and grey the remainder. The denominator includes all assessed species in the chosen release, including Data Deficient and extinct categories. Consequently, these percentages are not the Red List’s separate best estimates of extinction risk among living, data-sufficient species. They answer the narrower question of how the assessed records are distributed. The same definitions are used across all five groups, and the preceding count chart supplies the corresponding absolute totals. This consistency supports comparison while avoiding the assumption that unassessed or poorly documented species are free from threats.

Calculated from IUCN Red List 2025-1, Table 1b. Denominator: all assessed species, not only extant data-sufficient species.

11. African rhino populations, 2018–2024

White rhinos remain more numerous than black rhinos in these African population estimates, but the two series move in different directions. The white rhino total is lower in 2024 than in 2018, whereas the black rhino total rises across the three selected observations. Showing the species separately prevents the larger white rhino population from concealing the black rhino pattern within a combined total.

The observations are spaced three years apart. The joining lines help readers follow the series, but they do not show every annual movement between those dates. Published estimates can also be revised as survey coverage and methods change, so differences between successive reports should be interpreted with that qualification. The IUCN’s 2025 reporting highlighted drought and other pressures as well as poaching. Population totals alone cannot separate the effects of those causes. The photograph below connects the lighter series to a white rhinoceros, and the linked reports provide the original estimates for both species.

Sources: IUCN report (2022), 2018 and 2021 estimates; IUCN report (2025), 2024 estimates. Three-year intervals; intermediate annual fluctuations not shown.

12. Gestation lengths in selected mammals

The African bush elephant has the longest gestation among these selected mammals, at about twenty-two months in the database. White rhinos and giraffes also carry their young for well over a year, whereas rabbits and house mice complete pregnancy in a small fraction of that time. The comparison makes the range of mammalian reproductive schedules visible using a single consistent unit: days.

Gestation is only one part of reproductive pace. Litter size, age at maturity, survival and the interval before another birth all influence how quickly a population can grow. A long pregnancy therefore does not by itself predict a species’ conservation status, but it helps explain why replacing lost adults may be slow in some large mammals. These are selected database values rather than fixed durations for every individual. They also do not measure total parental care after birth. Read alongside the rhino population chart, the figures add biological context to the time required for recovery and the importance of protecting breeding animals.

Source: AnAge, build 15 (2023), João Pedro de Magalhães / HAGR. Data licensed CC BY 3.0; days shown as published.

13. Animal kingdom data table

Compare 84 animals by body weight, longevity and reproduction. Scroll down and sideways to explore the table. Values come from AnAge build 15 (2023); a dash means no value is supplied. Maximum lifespans are individual records or estimates, not average life expectancy. Weight and reproductive values vary between individuals. Gestation applies to mammals; incubation applies to egg-laying species. Young per litter or clutch may be an average. Scientific names follow the source dataset.