• It is for more than twenty years that at Maromizaha, in Madagascar, the protection project for the Indri indri, the singing lemur, has been under way.
• Thanks to their distinctive coat markings, it is possible to identify individuals without the need for collars.
• As well as being the largest lemur in the world, the Indri indri is also one of the most threatened.

In 2004, the first long-term monitoring project of an Indri indri population (the largest species of lemur) began in the New Protected Area (Nap) of the Maromizaha rainforest, in Madagascar. At the beginning of January, the collaboration between Friend of the Earth, U onlus, the Department of Life Sciences and Systems Biology at the University of Turin and Gerp (Groupe d'etude et de recherche sur les primates) enabled the launch of the Maromizaha conservation project, with significant actions for the safeguarding and protection of this species. The project's main objectives are built on three strategies: monitoring the indri population, restoring the habitat and involving the local community.

The Maromizaha conservation project

Currently, 14 family groups of indri are under observation. The monitoring work consists of daily observation of both individual animals and entire family groups. Identification is made easier by the coat markings that distinguish individual specimens, thus avoiding the need to fit them with dedicated collars. A further avenue of research is acoustic, with specific recorders placed to monitor spatial presence and sound characteristics. Finally, a very important part of the project's success is raising awareness among local communities, involving them directly in the activities carried out in the area.

The Indri indri, the singing lemur

For those unfamiliar with the Indri indri, it is the largest lemur in Madagascar's forests and, therefore, in the world. Its defining characteristic is its song. To communicate, it uses a song with sequences that can last up to three minutes. But what makes it so special? The rhythm: the indri is the only lemur capable of composing rhythmic sound sequences, with harmonised duets and choruses.

Among singing primates, only a few families display this type of signal: gibbons, tarsiers and titis, not forgetting humans. These singing lemurs have a thick black coat with white patches that distinguish one from another, a fox-like muzzle and large green eyes. Across Madagascar there are approximately 5,000 indri; however, habitat destruction combined with hunting and climate change mean that the indri is one of the most threatened lemurs in the world.

The interview with Clarissa Puccioni

Working on the Friend of the Earth project for the World sustainability organization (Wso) is Italian science communicator Clarissa Puccioni, with whom we had a chat about her experience in Madagascar and the features of the project to protect the Indri indri.

Let's start from the beginning: what is your story and how did you end up in Madagascar?
I have always been surrounded by nature, as I live in the countryside. By the age of eight I already knew what the term "ethology" meant, and because of this my desire was to study animal behaviour. I thus began a course of study in natural sciences which, however, due to personal circumstances, I was unable to complete. Despite that, I spent eight years as a science communicator focusing on African mammals, in particular big cats, elephants and rhinos, and together with various associations I helped raise awareness of the reality of trophy and canned hunting. I also had several experiences in the conservation of amphibians, reptiles, butterflies, and an internship in Madagascar working on the Maki catta [another lemur species, ed.]. In 2019 I conducted a behavioural study on the psychophysical rehabilitation of the Lemur catta, the ring-tailed lemur, in the south-west of the island, more precisely at the rehabilitation centre of the Reniala reserve; that is where I met my Malagasy partner Germain, the centre's zookeeper and a local guide, and from that moment I decided I wanted to settle there.

Why was the decision made to fund this project on the Indri indri?
I had long been aware of the Maromizaha project run by the Department of Life Sciences and Systems Biology at the University of Turin. Friend of the Earth, in addition to certifying products from agricultural and textile activities as sustainable, has a section dedicated to existing projects that need funding for their conservation activities. Wanting to support a primate project, I selected precisely the Maromizaha Project, which not only works to expand knowledge of the Indri indri species in order to protect it, but also focuses on the inclusion of the local population of the village of Anevoka through awareness-raising, green classes, training for local guides at Maromizaha and socioeconomic support on the ground.

What are the main threats facing the Indri indri and what are the greatest difficulties for conservation?
The indri is a flagship species, closely tied to its ecosystem, which needs to be protected alongside it. The tavy practice, which in Malagasy means "slash-and-burn", is still widely used by the local population to extend their farmland. Despite the species being protected by local fady or taboo, as the people believe it embodies the spirit of their ancestors, it is hunted for its meat and fur. In 2018, poachers killed nine indri in the municipality of Lakato. The difficulties therefore lie in finding a point of compromise between the existence of the indri and the socioeconomic needs of the community — a balance that this project has nevertheless managed to strike and continues to pursue.

How do the rhythmic vocalisations work, and why do they make the indri so similar to humans?
Valeria Torti, the project's research technician, answered this question. The indri's song, just like human song, can be codified through a series of "rules" that are intrinsic to human musicality, such as rhythm. In humans there exists a kind of "universal" rhythm — that is, a rhythmic structure found across all music produced by our species. What researchers at the University of Turin discovered is that the indri's songs contain identifiable rhythmic categories in which the interval is isochronous (1:1) — meaning the intervals between one sound and the next have exactly the same duration — or double the first (1:2), one of the most widespread patterns in human music. What is more, indri sing with a ritardando, that is, a gradually slowing tempo, which is peculiar to several human musical traditions. This discovery is significant because, until now, universal rhythms had only been identified in certain bird species, where only the presence of an isochronous rhythm (1:1) had been observed, and not of other rhythmic categories.

What is the fieldwork based on, and how are the animals studied?
The Maromizaha project allows Italian and Malagasy students to carry out monitoring activities in the heart of the forest, thanks to the multi purpose centre — the first wooden structure with tent spaces to serve as an Italian research centre in Madagascar, conceived by Professor Cristina Giacoma and her research group in Turin. Students monitor groups of indri, but also the diademed sifaka and the bamboo lemur, both closely tied to the forest. Every five minutes they record behaviours on paper grids using the focal sampling method, and they capture vocalisations using AudioMoth recorders (exploiting PAM — Passive Acoustic Monitoring), which are subsequently analysed in a laboratory in Italy.

Bioacoustics is a field that is gaining ever more ground thanks to new discoveries. Is this due to the development of new technologies and instruments, or is the perspective shifting? What might future scenarios look like?
Here too it was Valeria Torti who spoke. Bioacoustics is a discipline that, over the last decade, has seen a marked increase in attention from the scientific community, both for its versatility of application and for the technological progress that has made effective instrumentation accessible at affordable costs. Classically, bioacoustics has been applied to the study of animal vocal signals, with the aim of understanding both how animals communicate and how to differentiate species, individuals and groups. The study of sounds in the animal world has also played a role in understanding the evolutionary mechanisms that led to the emergence of the human species, by investigating the similarities and differences that can be found with human language and music. This approach, for example, allows us to build an evolutionary tree of musical traits and understand how musical abilities originated and evolved in humans.

A major area of application for this discipline is, furthermore, monitoring. The vocal signals emitted by animals are a means through which researchers monitor and track — think of migratory birds or cetaceans — animals in their natural environments. Over the last decade, thanks to the development and commercialisation of affordable yet technologically advanced devices (which can, for instance, be managed remotely), the role of bioacoustics in environmental monitoring has taken hold, and passive acoustic monitoring is an increasingly common topic of discussion. Through the use of passive acoustic recorders, which are controlled remotely and/or installed in the field for many months, it is possible to monitor animal populations across a wide geographical scale, reducing both human disturbance of populations and monitoring costs. The current scenario sees an intensification of this monitoring practice, applied to a great many species across the most varied environments. In the future, monitoring will be integrated, open source, and large quantities of data will be made available for species research and conservation.

How far along are we with the project's objectives?
The project was founded in 2004 and the new protected area of Maromizaha has held that status since 2015; several objectives have been achieved to date, among them the division of the land at the edge of the virgin primary forest of Maromizaha into numbered agricultural plots: each family in the village of Anevoka, on the slopes of the area, has been assigned a plot so that they can sustain themselves through rice cultivation and thus avoid further deforestation. Fish-farming ponds, a honey production facility, orchards and a primary school have also been created. This year, Friend of the Earth has made it possible to continue reforestation activities, previously funded by Uiza and several zoos in Italy. Around thirty seedlings of the endemic bamboo species volohasy, in the local language, have been planted in a degraded area. Thanks to our support, two small SM4 recorders were also purchased to continue passive acoustic monitoring.