Search

The natural world is full of examples of animals interacting with their physical environment in surprising ways: capuchin monkeys crack open nuts with rocks; dolphins use sponges as 'gloves' on their rostra when searching for prey on the sea floor; and New Caledonian crows manufacture stick tools to pull grubs from logs (Figure 1). Deeper into the phylogenetic tree we continue to see interesting examples of behaviors of this kind, such as octopuses using coconut shells for protection, tuskfish breaking open cockles by hitting them against coral heads, and bees learning to pull string to gain out-of-reach food. These sophisticated behavioral interactions with their physical environment suggest that animals might have a deep understanding of their physical world at a cognitive level. In this primer, we review the performances of a variety of species when faced with tasks that probe their understanding of their physical world. In this Primer, Alex Taylor and Melissa Johnston examine the performances of animals when faced with tasks that probe their understanding of the physical world. [ABSTRACT FROM AUTHOR]

Ecoacoustics—or acoustic ecology—aids in monitoring elusive and protected species in several ecological contexts. For example, passive acoustic monitoring (PAM), which involves autonomous acoustic sensors, is widely used to detect various taxonomic groups in terrestrial and aquatic ecosystems, from birds and bats to fish and cetaceans. Here, we illustrate the potential of ecoacoustics to monitor soil biodiversity (specifically fauna)—a crucial endeavour given that 59% of species live in soil yet 75% of soils are affected by degradation. We describe the sources of sound in the soil (e.g. biological, geological and anthropogenic) and the ability of acoustic technology to detect and differentiate between these sounds, highlighting opportunities and current gaps in knowledge. We also propose a roadmap for the future development of optimized hardware, analytical pipelines and experimental approaches. Soil ecoacoustics is an emerging field with considerable potential to improve soil biodiversity monitoring and 'soil health' diagnostics. Indeed, early studies suggest soil ecoacoustics can be successfully applied in various ecosystems (e.g. grasslands, temperate, tropical and arid forests) and land uses (e.g. agriculture, viticulture, natural and restored ecosystems). Given the low cost, minimal intrusiveness, and effectiveness in supporting soil biodiversity assessments and biosecurity risks, we advocate for the advancement of soil ecoacoustics for future land management applications. [ABSTRACT FROM AUTHOR]

Restoring and monitoring soil biodiversity has never been more important. Ecoacoustics is emerging as a promising tool to detect and monitor soil biodiversity and was recently effective in a temperate forest context. However, there is a need to investigate the efficacy of soil ecoacoustics in other ecosystems and bioregions. Here, we applied ecoacoustics tools and indices (Acoustic Complexity Index, Bioacoustic Index, Normalised Difference Soundscape Index) to measure soil biodiversity in an Australian grassy woodland restoration chronosequence, spanning three age classes. We collected n = 240 soil acoustic samples from two cleared plots (continuously cleared through active management), two woodland plots undergoing restoration (revegetated 14–15 years ago) and two plots of remnant vegetation over 5 days in Mount Bold, South Australia. We used a below‐ground sampling device and sound attenuation chamber to record soil invertebrate communities, which were also manually counted. We found that acoustic complexity and diversity were significantly higher in revegetated and remnant plots than in cleared plots, both in‐situ and in sound attenuation chambers. The acoustic complexity and diversity also significantly associated with soil invertebrate abundance and richness. Synthesis and applications. Our results provide new support that ecoacoustics can help monitor soil biodiversity in different forest restoration contexts, including in UK temperate and Australian grassy woodlands. This technology holds promise in addressing the global need for effective soil biodiversity monitoring methods and protecting our planet's most diverse ecosystems. [ABSTRACT FROM AUTHOR]

There is no conclusive evidence of any nonhuman animal using the sun as part of its predation strategy. Here, we show that the world's largest predatory fish-the white shark (Carcharodon carcharias)-exploits the sun when approaching baits by positioning the sun directly behind them. On sunny days, sharks reversed their direction of approach along an east-west axis from morning to afternoon but had uniformly distributed approach directions during overcast conditions. These results show that white sharks have sufficient behavioral flexibility to exploit fluctuating environmental features when predating. This sun-tracking predation strategy has a number of potential functional roles, including improvement of prey detection, avoidance of retinal overstimulation, and predator concealment.

Humans are capable of simply observing a correlation between cause and effect, and then producing a novel behavioural pattern in order to recreate the same outcome. However, it is unclear how the ability to create such causal interventions evolved. Here, we show that while 24-month-old children can produce an effective, novel action after observing a correlation, tool-making New Caledonian crows cannot. These results suggest that complex tool behaviours are not sufficient for the evolution of this ability, and that causal interventions can be cognitively and evolutionarily disassociated from other types of causal understanding.

Introduction: Literature indicating that transcranial photobiomodulation (tPBM) may enable the brain to recover normal function after concussion, resulting in symptoms reduction, and improved cognitive function after concussion is limited by small sample sizes and lack of controls. Methods: We conducted a randomized, double-blind, placebo-controlled trial examining the effect of 6 wk of tPBM in patients 11 yr or older who received care for persistent postconcussion symptoms between September 2012 and December 2015. Our primary outcome measure was the mean difference in Postconcussion Symptom Scale total score and the raw Immediate Postconcussion Assessment and Cognitive Testing composite scores between study entry and treatment completion. Participants received two, 10-min sessions either with tPBM units or via two placebo units, three times per week. We screened for potential confounding variables using univariable analyses. We entered covariables that differed between the two groups on univariable screening into a regression analysis. We considered adjusted odds ratio that did not cross one statistically significant. Results: Forty-eight participants completed the study. Most were female (63%), and a majority sustained their injury during sports or exercise (71%). Despite randomization, those that received tPBM therapy reported a greater number of previous concussions. After adjusting for the effect of previous concussions and multiple comparisons, there were no significant differences between tPBM and placebo groups at 3 or 6 wk of treatment. Conclusions: Despite showing promise in previous investigations, our study did not show benefit to tPBM over placebo therapy in patients experiencing persistent postconcussion symptoms. Further investigation is needed to determine if varying the dose or timing alters the efficacy of tPBM after concussion. [ABSTRACT FROM AUTHOR]