Maarg Manthan · Topic 3.3

Methodology of Tiger Census and Lion Census

Environment & Ecology › Population Ecology and Species Interactions · Topic 3.3

India estimates its tiger population every four years in the All India Tiger Estimation, AITE, conducted by the National Tiger Conservation Authority with the Wildlife Institute of India and state forest departments. The method has three phases: Phase I collects data on tiger signs, prey, habitat and human disturbance by foot surveys; Phase II uses camera traps to photograph tigers, whose unique stripe patterns identify individuals, and applies capture-mark-recapture statistics; Phase III analyses data with remote sensing and statistics. The older pugmark method was dropped because of errors. The 2022 AITE estimated 3,682 tigers, with a range of 3,167 to 3,925, against 2,967 in 2018. The Asiatic lion census in Gujarat is done every five years by the state Forest Department by the direct beat verification method, which counted 674 lions in 2020.

5 min read · UPSC Prelims · Environment & Ecology · Population Ecology and Species Interactions

At a Glance

Tiger estimate Every 4 years, AITE
Latest tigers 3,682 in 2022
Method Camera traps, mark-recapture
Lion census Every 5 years, Gir
Lion method Direct beat verification
Exam link UPSC Prelims, Environment & Ecology: Population Ecology and Species Interactions

Where Does It Fit?

This topic follows the account of population ecology. It shows how the methods of estimating populations are applied to two flagship species of India. Previous topic: Population Ecology and Population Growth Models. Next topic: Adaptation in Plants and Animals: Examples.

How Is the Tiger Population Estimated?

Aspect	Details
Agency	The National Tiger Conservation Authority (NTCA), Wildlife Institute of India (WII) and state forest departments. The cycle is every four years
Phase I	Field survey: foot-line transects to record tiger signs (scat, pugmarks, scratches), prey density, and human disturbance, using the M-STrIPES mobile app
Phase II	Camera trapping in sample areas: paired cameras photograph both flanks of each tiger, and unique stripe patterns identify individuals
Phase III	Remote sensing and GIS analysis of habitat and forest change
Capture-mark-recapture	Statistical model that uses the number of tigers photographed again to estimate the total population and its error range
Double sampling	Combines sign surveys across a large area with camera trap estimates in a smaller area
M-STrIPES	Monitoring System for Tigers: Intensive Protection and Ecological Status, launched in 2010 for patrolling and monitoring

What Are the Results and the Lion Census Method?

Tiger numbers: 1,411 (2006), 1,706 (2010), 2,226 (2014), 2,967 (2018) and 3,682 (2022); the 2022 range is 3,167 to 3,925; India has about 75 percent of the world’s wild tigers
Release: the 2022 results were released on 29 July 2023, Global Tiger Day, by the Environment Minister
Pugmark method: used earlier, it was criticised as inaccurate and replaced by camera traps
Project Tiger: launched on 1 April 1973 at Jim Corbett National Park
Lion census: done in Gir and nearby areas of Saurashtra every five years by the Gujarat Forest Department
Direct beat verification: staff and volunteers move in lines through the forest over two days and count lions seen directly, with checks to avoid double count
Lion numbers: 411 (2010), 523 (2015), 674 (2020); a count in 2025 was reported by Gujarat as 891, which should be checked
Gir: the only home of the wild Asiatic lion, Panthera leo persica

What Else Should You Remember?

Camera trap: a motion triggered camera used to record wildlife
Stripe pattern: like fingerprints, unique to each tiger
Scat DNA: DNA analysis from droppings is used to identify individuals
Occupancy modelling: estimates the share of area used by a species
Water hole and sign surveys: used for lions and other animals
Point count: a method for lions to count at water points
Block count: counting animals in blocks
Line transect: counting along lines to estimate density
Mark and recapture: used for fish, butterflies and rodents
Leopard and other estimates: NTCA also reports leopards, with about 13,874 in 2022 report
Elephant census: Synchronous census every five years; 29,964 in 2017
Rhino counts: Assam counts one-horned rhinos by annual surveys
Cheetah project: cheetahs were brought from Namibia in 2022 to Kuno
Tiger reserves: over 50 reserves cover about 2.4 percent of India’s area
Global Tiger Day: 29 July
St Petersburg Declaration: 2010 commitment to double wild tigers by 2022, which India achieved earlier
TX2: the global goal of doubling tigers
Link: statistics of population are in Population Ecology and Population Growth Models
Link to protected areas: see Protected Area Network and Species-Based Conservation Programmes
Caution: check the latest census figures before writing answers
Sampling design: grids of a few square kilometres are used to place camera traps and survey plots
Error range: estimates are given with confidence limits, because exact counts are impossible
Cub and camera: young cubs are not counted if they are not photographed, which is why a range is reported
Cooperation: state forest staff, volunteers and researchers all take part in the fieldwork
Leopard counts: leopards were also estimated from the same camera data

Why Does It Matter for the Exam?

Frequency: tiger 4 years, lion 5 years
Tiger 2022: 3,682
Lion 2020: 674
Current affairs link: new AITE cycle and lion counts
Common errors: confusing pugmark with camera trap or giving the wrong year

As an analytical point, scientific, camera-based methods give reliable estimates with error ranges, and rising counts show success of protection. Habitat connectivity and conflict with people become the next challenges as tiger numbers rise.

Why Is This Topic Important?

Method Camera traps
Numbers Trends
Lions Direct count

What Came Next?

The next topic covers adaptation in plants and animals. Next topic: Adaptation in Plants and Animals: Examples.

Key People and Terms

AITE All India Tiger Estimation
NTCA National Tiger Conservation Authority
M-STrIPES Tiger monitoring app
Camera trap Motion triggered camera
Capture-recapture Statistical estimate method
Direct beat verification Lion counting method

Exam Corner

Points to Remember

AITE every 4 years; lion census every 5 years.
2022 tigers: 3,682.
2018 tigers: 2,967.
Lions 2020: 674.
Project Tiger: 1 April 1973.

Do Not Confuse With

Pugmark and camera trap Old unreliable versus modern individual identification
NTCA and WII Authority versus research institute
Tiger and lion method Camera trap statistics versus direct beat count

Memory Hook

Four-year tiger, five-year lion; stripes in cameras, beats in Gir.

Mains Angle

Questions ask for methods, frequency and numbers. These points help.

Methods Science
Trend Numbers
Challenges Conflict

A Question You May Face

An original practice question, not a past paper question.

“Describe the scientific method used for estimating the tiger population in India and discuss the challenges that come with rising numbers.”

How to Answer

Method Three phases.
Data Trend.
Lions Beat count.
Challenges Space, conflict.

GS Relevance

Prelims: method, frequency, latest numbers, agencies, apps. GS Paper 3: wildlife conservation.

Frequently Asked Questions

How is the tiger population estimated in India?

The All India Tiger Estimation is done every four years by the National Tiger Conservation Authority and the Wildlife Institute of India. It combines field surveys of tiger signs and prey, camera trapping that identifies individual tigers by their stripe pattern, and statistical models of capture and recapture, with remote sensing to study habitat.

What was the tiger population in the 2022 estimate?

The 2022 All India Tiger Estimation reported a minimum of 3,167 and an upper estimate of 3,925 tigers, with an average of 3,682, which is up from 2,967 in 2018. India holds about 75 percent of the world's wild tigers, and the results were released in July 2023.

Why was the pugmark method replaced?

The pugmark method, in which footprints were collected and counted, was found to be inaccurate because it is hard to tell individual tigers apart by tracks, and the method is affected by the soil, the observer and the season. Camera traps with stripe identification and statistical models give more reliable estimates.

How are Asiatic lions counted?

Asiatic lions in Gir and nearby areas of Gujarat are counted every five years by the state Forest Department using the direct beat verification method. Staff and volunteers walk through the forest in lines and record lions they see directly, and the data are checked to avoid double counting. The 2020 count was 674 lions.

What is M-STrIPES?

M-STrIPES, the Monitoring System for Tigers: Intensive Protection and Ecological Status, is a software and mobile application launched in 2010 by the NTCA to help forest staff record patrol routes, tiger signs, threats and human disturbance in the field, and to map the data on a GIS platform.

PYQ Practice — Statement Analysis

1 India estimates its tiger population every four years.

True

By the NTCA and WII.

2 The pugmark method is the present main method for counting tigers.

False

Camera traps replaced it.

3 The lion census in Gir is conducted every five years.