On Saturday (February 7), the Gujarat Forest Department and the zoology department of the Maharaja Sayajirao University of Baroda (MSU) concluded a two-day crocodile census, conducted on a 17.5 km stretch of the Vishwamitri river in Vadodara. The departments will now analyse the data from it.
This census comes a year after the Gujarat Ecological Education and Research (GEER) Foundation (an autonomous body set up by the state forest department) conducted the previous iteration. It is also the first since the Vadodara Municipal Corporation (VMC) completed the river’s first-ever dredging and desilting as part of the Rs 1,200-crore Vishwamitri Flood Mitigation Project. Before 2025, the exercise was conducted in 2020.
Ranjitsinh Devkar, assistant professor of zoology at MSU, who is heading the current year’s census, told The Indian Express that the exercise was aimed more at bringing out “in-depth” research on the behavioural patterns and population structure of the muggers within city limits of the river than confirming the number of crocodiles therein.
Not just about the numbers
Devkar, who also prepared the programme for the GEER Foundation-led 2025 census, said that the census was aimed at getting an insight into five important aspects of crocodiles inhabiting the Vishwamitri, making Vadodara a unique city to have marsh crocodiles or muggers (Crocodylus palustris) in their natural habitat among human population. “We are counting the numbers, of course, but the interest is in analysing the population structure as per age, size, class, and distribution of the crocodiles. Third, we will conduct an occupancy survey of the zones; the other two aspects are to study the basking behaviour and sites as well as the location of the dens, comparing with what was seen and recorded in the 2025 census,” he said.
Crocodile numbers are only a part of the larger need of profiling the characteristics of the reptile population within city limits, he added. “We are analysing the data to understand how the crocodiles present in the Vishwamitri riverine area fetch food, propagate, build dens and if they show spatial recognition. When crocodiles are in their fertile age, they can live their cycle successfully… Our focus is on classifying crocodiles as per size and distribution.”
Understanding crocodile behaviour
The census comes close to a year after the VMC undertook dredging and desilting of the river. Devkar said that the data of this census will help researchers compare any shift in the muggers’ pattern or behaviour after the change in the riverine system and removal of debris and solid waste from the river.
During the sighting undertaken for the census, the teams spotted more basking crocodiles as well as big freshwater turtles – a first-of-its-kind phenomenon that will now be analysed. Devkar said, “Much of the vegetation from the riverbank is now gone… There are not as many thickets as they were earlier. We can see more basking crocodiles. So, we will study if the crocodiles have developed a liking for open banks or found more space, or possibly earlier they were not spotted due to the thick vegetation… Similarly, we are seeing big freshwater turtles basking around the crocodiles too.”
Story continues below this ad
He added that as per their nature, crocodiles “should ideally resist a change” and the census will help understand the impact of the changes on the reptile population – and whether it shows spatial fidelity (tendency to return to or remain within specific, familiar locations over time) towards basking sites and dens. “If there was a den existing earlier, does it use the same den? Or if the den has been disturbed or destroyed, does it make a new den? It is a pure question of research. Understanding the behaviour of reptiles, we will be able to understand how to manage the population of the urban stretch. If it shows spatial fidelity, it would mean that the site has to be maintained without disturbance.”
How the census was carried out
The census saw the 17.5 km of the Vishwamitri within the VMC’s jurisdiction being divided into ten sections. In each of the sections, a team of five – three students of MSU’s zoology department, a volunteer from an NGO, and a forest guard – undertook the daytime sighting and nocturnal count. Since crocodiles are predominantly nocturnal, the technique of “colour code” was used after dark. This involves spotting their fire-red eyes, which distinguishes them from other aquatic species as well as animals that can be part of the river banks.
“We have enhanced the census protocols compared to last year. Apart from the plain sighting and counts during the day, the teams also classified the crocodiles by (length): less than 1 metre (m), 1-3 m, and more than 3 m. The crocodiles who are 1-3 m in length have reached adulthood, and (those) under 1 m are sub-adults or juveniles. It is usually muggers approximately 2.5-3 m in size that are dangerous to go close to… We will analyse the data to understand how the population is distributed in the zones, as per the size of the crocodile. Zones with a higher number of crocodiles of 2.5-3 m in size will be classified as high-risk zones. We will make recommendations to ensure that the human footfall in these areas is less… to avoid conflicts.”
The 2025 census had recorded 442 crocodiles in a 25-km stretch of the river. Following that, a committee of environmental experts, formed by the Gujarat State Human Rights Commission to supervise the initial phase of the flood mitigation project, reported that the reptile was being “spotted in clusters” as against its instinct of inhabiting the river in a scattered manner. The census data cited in the report had noted how the highest density of crocodiles was found in the section of the river that passes through the busier part of Vadodara city, “deviating from natural instincts”.
