Welcome to the I Can't Sleep Podcast,
Where I help you drift off one fact at a time.
I'm your host,
Benjamin Boster,
And today's episode is about tigers.
The tiger is a large cat and a member of the genus Panthera,
Native to Asia.
It has a powerful,
Muscular body with a large head and paws,
A long tail,
And orange fur with black,
Mostly vertical stripes.
It is traditionally classified into nine recent subspecies,
Though some recognize only two subspecies.
Mainland Asian tigers and the island tigers of the Sunda Islands.
Throughout the tiger's range,
It inhabits mainly forests,
From coniferous and temperate broadleaf,
And mixed forests in the Russian Far East and Northeast China,
To tropical and subtropical moist broadleaf forests on the Indian subcontinent and Southeast Asia.
The tiger is an apex predator and preys mainly on ungulates,
Which it takes by ambush.
It lives a mostly solitary life and occupies home ranges,
Defending these from individuals of the same sex.
The range of a male tiger overlaps with that of multiple females,
With whom he mates.
Females give birth to usually two or three cubs that stay with their mother for about two years.
When becoming independent,
They leave their mother's home range and establish their own.
The tiger is among the most popular of the world's charismatic megafauna.
It has been kept in captivity since ancient times and has been trained to perform in circuses and other entertainment shows.
The tiger featured prominently in the ancient mythology and folklore of cultures throughout its historic range and has continued to appear in culture worldwide.
The Old English tigris derives from Old French tigre,
From Latin tigris.
Since ancient times,
The word tigris has been suggested to originate from the Armenian or Persian word for arrow,
Which may also be the origin of the name for the river Tigris.
However,
Today the names are thought to be homonyms and the connection between the tiger and the river is doubted.
In 1758,
Carl Linnaeus described the tiger in his work Systema Naturae and gave it the scientific name Felis tigris,
As the genus Felis was being used for all cats at the time.
His scientific description was based on descriptions by earlier naturalists,
Such as Conrad Gessner and Ulisse Adrovandi.
In 1929,
Reginald Innes Pocock placed the species in the genus Panthera,
Using the scientific name Panthera tigris.
Nine recent tiger subspecies have been proposed between the early 19th and early 21st centuries,
Namely the Bengal,
Malayan,
Indochinese,
South China,
Siberian,
Caspian,
Javan,
Bali,
And Sumatran tigers.
The validity of several tiger subspecies was questioned in 1999,
As most putative subspecies were distinguished on the basis of fur length and coloration,
Striping patterns and body size of specimens in natural history museum collections that are not necessarily representative for the entire population.
It was proposed to recognize only two tiger subspecies as valid.
Namely P.
T.
Tigris in mainland Asia,
And the smaller P.
T.
Sundica in the greater Sunda Islands.
The two subspecies proposal was reaffirmed in 2015 through a comprehensive analysis of morphological,
Ecological,
And mitochondrial DNA traits of all putative tiger subspecies.
In 2017,
The Cat Classification Task Force of the IUCN Cat Specialist Group revised felid taxonomy in accordance with the 2015 two subspecies proposal and recognized only P.
T.
Tigris and P.
T.
Sundica.
Results of a 2018 whole genome sequencing study of 32 samples from 6 living putative subspecies the Bengal,
Malayan,
Indochinese,
South China,
Siberian,
And Sumatran tiger found them to be distinct and separate clades.
These results were corroborated in 2021 and 2023.
A 2023 study found validity for all 9 recent subspecies.
The Cat Specialist Group states that given the varied interpretations of data the subspecific taxonomy of this species is currently under review by the IUCN SSC Cat Specialist Group.
The tiger shares the genus Panthera with the lion,
Leopard,
Jaguar,
And snow leopard.
Results of genetic analyses indicate that the tiger and snow leopard are sister species whose lineages split from each other between 2.
7 and 3.
7 million years ago.
The tiger's whole genome sequencing shows repeated sequences that parallel those in other cat genomes.
Tigers can interbreed with other Panthera cats and have done so in captivity.
The liger is the offspring of a female tiger and a male lion,
And the taigan the offspring of a male tiger and a female lion.
The lion sire passes on a growth-promoting gene,
But the corresponding growth-inhibiting gene from the female tiger is absent,
So that ligers grow far larger than either parent species.
By contrast,
The male tiger does not pass on a growth-promoting gene,
While the lioness passes on a growth-inhibiting gene.
Hence,
Taigans are around the same size as their parents.
Since they often develop life-threatening birth defects and can easily become obese,
Breeding these hybrids is regarded as unethical.
The tiger has a typical felid morphology,
With a muscular body,
Shortened legs,
Strong forelimbs with wide front paws,
A large head and a tail that is about half the length of the rest of its body.
It has five digits,
Including a dewclaw on the front feet and four on the back.
All of which have retracto-claws that are compact and curved and can reach 10 cm long.
The ears are rounded and the eyes have a round pupil.
A snout ends in a triangular pink tip with small black dots,
The number of which increase with age.
The tiger's skull is robust,
With a constricted front region,
Proportionally small,
Elliptical orbits,
Long nasal bones,
And a length in cranium,
With a large sagittal crest.
It resembles a lion's skull,
But differs from it in the concave or flattened underside of the lungs.
It has a smaller jaw and its longer nasals.
The tiger has 30 fairly robust teeth,
And its somewhat curved canines are the longest in the cat family,
At 6.
4 to 7.
6 cm.
The tiger has a head-body length of 1.
4 to 2.
8 m,
With a 0.
6 to 1.
1 m tail,
And stands 0.
8 to 1.
1 m at the shoulder.
The Siberian and Bengal tigers are the largest.
Male Bengal tigers weigh 200 to 260 kg,
Or 440 to 570 lbs,
And females weigh 100 to 160 kg,
Or 220 to 350 lbs.
Ireland tigers are the smallest,
Likely due to insular dwarfism.
Male Sumatran tigers weigh 100 to 140 kg,
And females weigh 75 to 110 kg.
The tiger is popularly thought to be the largest living felid species,
But since tigers of the different subspecies and populations vary greatly in size and weight,
The tiger's average size may be less than the lion's,
While the largest tigers are bigger than their lion counterparts.
The tiger's coat usually has short hairs,
Reaching up to 35 mm,
Though the hairs of the northern living Siberian tiger can reach 105 mm.
Belly hairs tend to be longer than back hairs.
The density of their fur is usually thin,
Though the Siberian tiger develops a particularly thick winter coat.
The tiger has lines of fur around the face,
And long whiskers,
Especially in males.
It has an orange coloration that varies from yellowish to reddish.
White fur covers the underside from head to tail,
Along with the inner surface of the legs and parts of the face.
On the back of the ears it has a prominent white spot,
Which is surrounded by black.
The tiger is marked with distinctive black or dark brown stripes,
Which are uniquely patterned in each individual.
The stripes are mostly vertical,
But those on the limbs and forehead are horizontal.
They are more concentrated towards the backside,
And those on the trunk may reach under the belly.
The tips of stripes are generally sharp,
And some may split up or split and fuse again.
Tail stripes are thick bands,
And a black tip marks the end.
The tiger is one of only a few striped cat species.
Stripes are advantageous for camouflage and vegetation,
With vertical patterns of light and shade,
Such as trees,
Reeds,
And tall grass.
This is supported by a furrier analysis study,
Showing that the striping patterns line up with their environment.
The orange color may also aid in concealment,
As the tiger's prey is colorblind,
And possibly perceives the tiger as green and blended in with the vegetation.
The three color variants of Bengal tigers,
Nearly stripless,
Snow white,
White,
And golden,
Are now virtually non-existent in the wild,
Due to the reduction of wild tiger populations,
But continue in captive populations.
The white tiger has a white background color,
With sepia brown stripes.
The golden tiger is pale golden,
With reddish brown stripes.
The snow white tiger is a morph,
With extremely faint stripes,
And a pale sepia brown ringed tail.
White and golden morphs are the result of an autosomal recessive trait,
With a white locus and a wide band locus,
Respectively.
The snow white variation is caused by polygenes,
With both white and white band loci.
The breeding of white tigers is controversial,
As they have no use for conservation.
Only 0.
001% of wild tigers have the genes for this color morph,
And the over-representation of white tigers in captivity is the result of inbreeding.
Hence,
Their continued breeding will risk both inbreeding depression,
And loss of genetic variability in captive tigers.
Pseudomelanistic tigers with thick merged stripes have been recorded in Simlipol National Park and three Indian zoos.
A population genetic analysis of Indian tiger samples revealed that this phenotype is caused by a mutation of a transmembrane aminopeptidase gene.
Around 37% of the Simlipol tiger population has this feature,
Which has been linked to genetic isolation.
The tiger historically ranged from eastern Turkey,
Northern Iran,
And Afghanistan,
To central Asia,
And from northern Pakistan through the Indian subcontinent,
And Indochina to southeastern Siberia,
Sumatra,
Java,
And Bali.
As of 2022,
It inhabits less than 7% of its historical distribution,
And has a scattered range in the Indian subcontinent,
The Indochinese peninsula,
Sumatra,
Northeastern China,
And the Russian Far East.
The tiger mainly lives in forest habitats,
And is highly adaptable.
Records in central Asia indicate that it primarily inhabited Dugai Riverine forests,
And hilly and lowland forests in the Caucasus.
In the Amur-Ussuri region of Russia and China,
It inhabits Korean pine,
And temperate broadleaf and mixed forests.
Riparian forests serve as dispersal corridors,
Providing food and water for both tigers and ungulates.
On the Indian subcontinent,
It inhabits mainly tropical and subtropical moist broadleaf forests,
Temperate broadleaf and mixed forests,
Tropical moist evergreen forests,
Tropical dry forests,
Alluvial plains,
And the mangrove forests of the Sundarbans.
In the eastern Himalayas,
It was documented in temperate forest up to an elevation of 4,
200 meters in Bhutan,
Of 3,
630 meters in the Mishmi Hills,
And of 3,
139 meters in Maidag County,
Southeastern Tibet.
In Thailand,
It lives in deciduous and evergreen forests.
In Sumatra,
It inhabits lowland peat swamp forests and rugged montane forests.
Camera trapping during 2010-2015 in the deciduous and subtropical pine forests of Jim Corbett National Park,
Northern India,
Revealed a stable tiger population density of 12 to 17 individuals per 100 square kilometers,
And an area of 521 square kilometers.
In northern Myanmar,
The population density in a sampled area of roughly 3,
250 square kilometers in a mosaic of tropical broadleaf forests and grassland was estimated to be 0.
21 to 0.
44 tigers per 100 square kilometers as of 2009.
Population density in mixed deciduous and semi-evergreen forests of Thailand's Wai Ka Kahang Wildlife Sanctuary was estimated at 2.
01 tigers per 100 square kilometers.
Camera trap data show that tigers in Chitwan National Park avoided locations frequented by people and were more active at night than during day.
In Sundarbans National Park,
Six radio-collared tigers were most active from dawn to early morning and reached their zenith around 7 o'clock in the morning.
A three-year-long camera trap survey in Shukla Funda National Park revealed that tigers were most active from dusk until midnight.
In northeastern China,
Tigers were crepuscular and active at night with activity peaking at dawn and dusk.
They were largely active at the same time as their prey.
The tiger is a powerful swimmer and easily transverses rivers as wide as 8 kilometers.
It immerses in water,
Particularly on hot days.
In general,
It is less capable of climbing trees than many other cats due to its size.
But cubs under 16 months old may routinely do so.
An adult was recorded climbing 10 meters up a smooth piple tree.
Adult tigers lead largely solitary lives within home ranges or territories,
The size of which mainly depends on prey abundance,
Geographical area,
And sex of the individual.
Males and females defend their home ranges from those of the same sex,
And the home range of a male encompasses that of multiple females.
Two females in the Sundarbans have home ranges of 10.
6 and 14.
1 square kilometers.
In Pana Tiger Reserve,
The home ranges of five reintroduced females varied from 53 to 67 square kilometers in winter to 55 to 60 square kilometers in summer and to 46 to 94 square kilometers during the monsoon.
Three males had 84 to 147 square kilometer large home ranges in winter 82 to 98 square kilometers in summer and 81 to 118 square kilometers during monsoon season.
In Sokoti Alin Biosphere Reserve,
14 females had home ranges 248 to 520 square kilometers and five resident males of 847 to 1923 square kilometers that overlapped with those of up to five females.
When tigresses in the same reserve had cubs of up to four months of age,
They reduced their home ranges to stay near their young and steadily enlarged them until their offspring were 13 to 18 months old.
The tiger is a long-ranging species and individuals disperse over distances of up to 650 kilometers to reach tiger populations in other areas.
Young tigresses establish their first home ranges close to their mothers while males migrate further than their female counterparts.
Four radio-colored females in Chitwan dispersed between 0 and 43.
2 kilometers and 10 males between 9.
5 and 65.
7 kilometers.
A sub-adult male lives as a transient in another male's home range until he is older and strong enough to challenge the resident male.
Scent markings allow an individual to pick up information on another's identity.
Unclaimed home ranges,
Particularly those that belong to a deceased individual,
Can be taken over in days or weeks.
Male tigers are generally less tolerant of other males within their home ranges than females are of other females.
Disputes are usually solved by intimidation rather than fighting.
Once dominance has been established,
A male may tolerate a subordinate within his range as long as they do not come near him.
The most serious disputes tend to occur between two males competing for a female.
Though tigers mostly live alone,
Relationships between individuals can be complex.
Tigers are particularly social at kills and a male tiger will sometimes share a carcass with the females and cubs within this home range and,
Unlike male lions,
Will allow them to feed on the kill before he has finished with it.
However,
A female is more tense when encountering another female at a kill.
During friendly encounters and bonding,
Tigers rub against each other's bodies.
Facial expressions include the defense threat,
Which involves a wrinkled face,
Bared teeth,
Pulled back ears and widened pupils.
Tigers will move their ears around to display the white spots,
Particularly during aggressive encounters and between mothers and cubs.
They also use their tails to signal their mood.
To show cordiality,
The tail sticks up and sways slowly,
While an apprehensive tiger lowers its tail or wags it side to side.
When calm,
The tail hangs low.
Tigers are normally silent,
But can produce numerous vocalizations.
They roar to signal their presence to other individuals over long distances.
This vocalization is forced through an open mouth as it closes and can be heard three kilometers away.
They roar multiple times in a row,
And others respond in kind.
Tigers also roar during mating,
And a mother will roar to call her cubs to her.
When tense,
Tigers moan,
A sound similar to a roar but softer,
And made when the mouth is at least partially closed.
Aggressive encounters involve growling,
Snarling and hissing.
An explosive coughing roar or coughing snarl is emitted through an open mouth and exposed teeth.
In friendlier situations,
Tigers prusten,
A soft,
Low-frequency snorting sound similar to purring in smaller cats.
Tiger mothers communicate with their cubs by grunting,
While cubs call back with meows.
When startled,
They woof.
They produce a deer-like pock sound for unknown reasons,
But most often it kills.
The tiger is a carnivore and an apex predator.
Abundance and body weight of prey species are assumed to be the main criteria for the tiger's prey selection,
Both inside and outside protected areas.
It feeds mainly on large and medium-sized ungulates.
It also preys opportunistically on smaller species like monkeys,
Peafowl and other ground-based birds,
Porcupines and fish.
Tigers learn to hunt from their mothers,
Though the ability to hunt may be partially inborn.
Depending on the size of the prey,
They typically kill weekly,
Though mothers must kill more often.
Families hunt together when cubs are old enough.
They search for prey using vision and hearing.
A tiger will also wade at a watering hole for prey to come by,
Particularly during hot summer days.
It is an ambush predator,
And when approaching potential prey,
It crouches with the head lowered and hides in foliage.
It switches between creeping forward and staying still.
A tiger may even doze off,
And can stay in the same spot for as long as a day,
Waiting for prey,
And launch an attack when the prey is close enough,
Usually within 30 meters.
If the prey spots it before then,
The cat does not pursue further.
A tiger can sprint 56 km per hour and leap 10 meters.
It is not a long-distance runner,
And gives up a chase if prey outpaces it over a certain distance.
While the lion represented royalty and power in Western culture,
The tiger played such a role in various Asian cultures.
In ancient China,
The tiger was seen as the king of the forest,
And symbolized the power of the emperor.
In Chinese astrology,
The tiger is the third out of 12 symbols in the Chinese zodiac,
And controls the period between 15 and 17 o'clock in the afternoon.
The year of the tiger is thought to bring dramatic and extreme events.
The white tiger is one of the four symbols of the Chinese constellations,
Representing the west along with the yin,
And the season of autumn.
It is the counterpart to the azure dragon,
Which conversely symbolizes the east,
Yang,
And springtime.
The tiger is one of the animals displayed on the Pashupati seal of the Indus Valley civilization.
The big cat was depicted on seals and coins during the Chola dynasty of southern India,
As it was the official emblem.
