All 9 Subspecies of Tigers

Tigers are the largest members of the cat family (Felidae) and one of the most charismatic endangered species on the planet.

Over the last century, tiger numbers have fallen by about 95 percent and tigers now survive in 40 percent less of the area they occupied just a decade ago, according to the World Wildlife Fund (WWF).

Tigers have the species name Panthera tigris. There are nine subspecies of tigers, three of which are extinct.

A meeting set to begin in Russia on Sunday (Nov. 21) will examine some of the issues facing tigers in the wild and efforts to better conserve the six surviving tiger subspecies. Here we look at what sets each of these species apart. 

1.Amur (or Siberian) tiger (Panthera tigris altaica)

Amur tigers (also known as Siberian, Manchurian, Ussurian, or Northeast China tigers) are the largest of the tiger subspecies. Males can grow up to more10.5 feet (3.3 m) from head to tail and weigh up to 660 pounds (300 kilograms). Females are smaller, reaching just 8.5 feet (2.6 m) in length and about 200 to 370 pounds (100 to 167 kilograms) in weight.

2.Indian (or Bengal) tiger (Panthera tigris tigris)

 

The most numerous of the tiger species, the Bengal tiger is found in India, Bangladesh, Nepal and Bhutan. India is home to the largest population, estimated to between 2,500 and 3,750 individuals, according to the Save the Tigers Fund.

3.South China tiger (Panthera tigris amoyensis)

Found in central and eastern China, the South China tiger is listed as Critically Endangered on the Red List one step higher than Endangered.
According to the WWF, the South China tiger is estimated to be functionally extinct. Currently 47 South China tigers live in 18 zoos, all in China, the WWF says.

4.Malayan tiger (Panthera tigris jacksoni)

The Malayan tiger was only identified as being a separate subspecies from the Indochinese tiger in 2004. It is very similar to the Indochinese tiger, but is smaller in size.

Malayan tigers are found in the tropical and subtropical moist broadleaf forests of the southern tip of Thailand and Peninsular Malaysia.

5.Indo-Chinese tiger (Panthera tigris corbetti)

Also known as Corbett's tiger, after British hunter and naturalist Jim Corbett, this subspecies is found in Cambodia, Laos, Burma, Thailand, and Vietnam and formerly in China. They are listed as endangered on the IUCN Red List.

6.Sumatran tiger (Panthera tigris sumatrae)

Found only on the Indonesian island of Sumatra, the Sumatran tiger is listed as Critically Endangered on the Red List.

Sumatran tigers are protected by law in Indonesia, with tough provisions for jail time and steep fines, according to the WWF. But despite conservation and anti-poaching efforts, tigers are still hunted and tiger parts and skins remain in high demand.

7.Bali tiger (Panthera tigris balica) - EXTINCT

One of the three extinct subspecies of tiger, the Bali tiger went extinct in the 1940's, according to the Save the Tigers Fund.

Tigers were last positively recorded in western Bali in the late 1930s, according to the IUCN.

The causes of extinction include hunting, loss of forest habitat and loss of their prey base. None of these tigers exist in captivity.

8.Javan tiger (Panthera tigris sondaica) - EXTINCT

This now-extinct species inhabited the Indonesian island of Java into the 1980's.

Tigers were last positively recorded from Java's Meru Betiri National Park in 1976, and likely disappeared from much of the rest of the island by the 1940s, according to the IUCN.

9.Caspian tiger (Panthera tigris virgata) - EXTINCT

The Caspian tiger (also called the Hyrcanian tiger or Turan tiger) became extinct in the 1970's.

Caspian Tigers and their large ungulate prey were found in the sparse forest habitats and riverine corridors west (Turkey) and south (Iran) of the Caspian Sea and west through Central Asia into the Takla Makan desert of Xinjiang, China, according to the IUCN.

Its extinction can be attributed to hunting of both tigers and their prey, habitat loss and conversion, and increased vulnerability of small populations.

How many fish can you keep in your tank?

Don't crowd your aquarium, it can only hold so many fish

There are guidelines about how many fish you can keep in an aquarium, but few experts would claim they are scientifically exact. The two main rules of thumb on stocking an aquarium are based respectively on the surface area of the tank (which influences oxygen levels) and the tank volume (this takes pollution as well as oxygen into account).

Many other things can alter how many fish an aquarium can healthily support, including:

• The shape of the aquarium
• The filtration system employed
• Surface agitation
• Water temperature
• Tank maintenance regime
• The kinds of fish being kept

Note: You can’t stock to the maximum capacity on first setting up! If your tank can hold, say, 20 small tropical fish, you should build up to that over a period of 3-6 months, to give the tank a chance to mature without a dangerous spike in pollutants.

With those caveats in place, let’s consider the common guidelines.

Fish cm per liter / fish inches per gallon

This was the rule I was taught when I first started keeping fish, and it’s still the most common stocking guide today.

1. Calculate the volume of your aquarium in liters or gallons
2. Work out the length of your chosen fish from nose to base of the tail
3. Consult the table below

Kind of fish       Inches / gallon     cm / liter
Coldwater            1" / gallon          2.5cm / 4.55 liters
Tropical             1" / 0.5 gallon      2.5cm / 2.25 liters
Marine (reef)        1" / 4 gallon        2.5cm / 18 liters
Marine (Fish-only)   1" / 2 gallons       5cm / 9 liters

For example, a 30-gallon aquarium could hold 30″ of coldwater fish, 60″ of tropical fish, or 15″ of marine fish.

Important: I am using Imperial (UK) gallons here. To work out US gallons, multiply UK gallons by 0.83 (or just stick to liters!)

The advantages of the fish inches per gallon rule are that it is easy to understand, since most people know their tank’s volume, and it takes into account the total volume of the tank. “The solution to pollution is dilution” is an old fishkeeping phrase. Bigger volumes of water can obviously carry more fish waste such as nitrate before there’s a problem.

The disadvantage of the rule is it does not take into account the tank shape. A tall, thin tank of 40-gallons will, according to this rule, have the same carrying capacity as a shallower, longer tank. But in reality the shallow tank will offer a much bigger surface area for gas exchange. In filter-less tanks particularly, it makes a big difference.

Fish length per unit of surface area

This rule puts aquarium surface area to the fore:

1. Calculate the surface area of the tank in square inches or centimeters
2. Work out the length of your chosen fish from nose to base of the tail
3. Consult the table below

Kind of fish    Inches / sq inches      cm / sq cm
Coldwater         1" / 30 sq inches        2.5cm / 190 sq cm
Tropical          1" / 12 sq inches        2.5cm / 75 sq cm
Marine            1" / 48 sq inches        2.5cm / 300 sq cm

A 36-inch long by 12-inch wide tank will therefore hold 14″ of coldwater fish, 36″ of tropical fish or 9″ of marine fish.

The advantage of using the surface area guideline is that it takes oxygen exchange directly into account. The ‘per gallon’ rule also does (that’s why coldwater fish need more gallons than tropicals) but not so directly.

The disadvantage of the rule is that people aren’t so aware of their tank’s surface area. It’s easy to work out: just multiply the width of the tank by the length. But it’s harder to keep in mind when you’re in the aquarium store wondering if you can add a few more fish.

Other issues with stocking levels

This article could run forever, so I’ll just add a few more caveats and pointers you should take into account.

Water displacement because of decoration means your tank won’t hold as much as its theoretical volume. Take off at least 10% to account for gravel, rocks, lots of bogwood and so on. With a very heavily furnished tank, take off 15%.

Different fish need a different amounts of space. Active fish like tangs or danios require more swimming room then relatively static fish like clownfish or neon tetras. Many fish require a certain-sized territory. For instance, I’d only keep one pair of dwarf cichlids in a two-foot freshwater aquarium. These measures have nothing to do with theoretical volume.

Big fish need more room than the equivalent number of little fish. Two six-inch long catfish will require a much bigger tank than 12 one-inch tetras. Their biological load is greater, and they’re messier eaters.

You can generally ignore shrimps, snails, plants and invertswhen making your calculations, as they have a small biological load and often contribute to the tank’s carrying capacity (such as plants which oxygenate by day or critters that clean up detritus). Two caveats: In large numbers they will make a difference (such as a snail infestation in a tropical tank), and marine inverts can be more sensitive to poorer water quality (hence the lower stocking suggestion per gallon above).

Strong water circulation, big filters, airstones and so on can increase the stocking level of your aquarium, but I wouldn’t recommend it. Better to have healthy fish with enough room to roam unmolested than to cram in another fish or two and risk disease and infighting.

Remember, these are just rules of thumb. Erring on the side of caution is always the best policy with aquariums, and an under-stocked tank is far easier to keep in good condition than even a slightly over-stocked one.