Why Scientists Have No Idea How Old Fungi Can Get

Fungi pop up everywhere. You spot them on fallen logs, in that slice of bread gone bad, even clinging to walls in damp bathrooms. Scientists have learned incredible things about these organisms, using them to develop medicines, study ancient life, and even explore the possibility of life on other planets. Yet here's the strange truth: researchers still cannot figure out something that seems basic. Nobody knows how old fungi can actually grow.

A team of scientists recently tried to tackle this overlooked puzzle. Their findings appeared in an opinion piece in Trends in Microbiology. Now, they are not claiming to have solved the mystery. Instead, they wanted to understand exactly why measuring fungal age feels so impossible. The researchers broke down both biological and practical reasons behind the problem. They also laid out some ideas for how future studies might finally make progress.

The issue runs deeper than just counting rings on a tree. The problem begins right at the very first step of studying any living thing: knowing where life starts and ends. For most creatures, this feels straightforward. An egg becomes an organism, and eventually that creature dies. Fungi do not play by these rules. These organisms grow as modular structures, meaning they consist of repeating units that look nearly identical. A underground network called mycelium spreads through soil or wood, constantly growing and changing. Some parts eventually break away or get broken down and reused by the organism itself.

This bizarre growth pattern leads to some genuinely strange questions. If a fungal network forms and later replaces most of itself, when did that fungus actually become "old"? If part of the network splits off and forms a separate piece but still carries the exact same DNA, are those two pieces still one individual or two? These might sound like philosophical riddles, but they represent real scientific obstacles.

One scientist at Lund University in Sweden, who served as the paper's senior author, put it bluntly. She said researchers currently cannot say whether ten years or five hundred years marks an "old" fungus. The diversity among fungal species adds another layer of difficulty. Each type seems to age in its own unique way, following completely different rules.

The research team admitted no quick fixes exist. However, they did propose some starting points. Scientists could compare genetic methods for tracking fungi over time. They might also study how genetic changes appear differently in long-lived versus short-lived specimens, similar to how botanists examine plant aging. Sequencing the mycelium's DNA could help too. Emerging tools like "fungi-on-a-chip" devices might eventually allow researchers to monitor tiny fungal changes under a microscope in ways that were never possible before.

The Swedish biologist expressed excitement about how much fundamental research remains to be done. She stressed that protecting fungal biodiversity and the essential services fungi provide to ecosystems depends on understanding their life cycles, including how and when their lives ultimately end. Without this knowledge, humans are essentially working blind when trying to conserve these ancient organisms that have shaped Earth's history for millions of years.