Within-island local variations in tooth wear of sika deer (Cervus nippon centralis) in northern Japan

Browsing into a Panamanian tropical rainforest: micro- and mesowear study of Central American red brocket deer

The Mazama genus is one of the more diverse genera among deer (Cervidae); its classification is controversial because of its complex phylogenetic relationships. The Central American red brocket deer (Mazama temama) is distributed from Central America to the northwest of South America. Studying the diet of mammals gives us information about the environment in which they live, considering that animals select food according to the resources available in the surrounding environment. Mesowear and microwear provide complementary data because they present direct evidence of feeding behaviour on different time scales. The use of extant animals as control samples or baselines allows for the interpretation of the results of a study performed using the archaeological record. For this reason, the aim of this paper was to study the diet of extant M. temama from Darien and to compare it with our previous results on ancient deer from Pedro Gonzalez Island archaeological site (6060–5620 cal yr BP) and extant individuals from San Jose Island (Panama). Evidence from the meso- and microwear analyses of M. temama from Darien suggests that they were browse-dominated mixed feeders during the last years of their lives and during the days before their death. There was no evidence of seasonal variation in their diets and between sexes. This paper exemplifies the potential of studying extant materials housed in museum collections as a reference to compare them to archaeological remains. The use of the same methods allows to construct baselines to better understand the archaeological record in the Neotropics.

Graphical Abstract

Tooth Diversity Underpins Future Biomimetic Replications

Although the evolution of tooth structure seems highly conserved, remarkable diversity exists among species due to different living environments and survival requirements. Along with the conservation, this diversity of evolution allows for the optimized structures and functions of teeth under various service conditions, providing valuable resources for the rational design of biomimetic materials. In this review, we survey the current knowledge about teeth from representative mammals and aquatic animals, including human teeth, herbivore and carnivore teeth, shark teeth, calcite teeth in sea urchins, magnetite teeth in chitons, and transparent teeth in dragonfish, to name a few. The highlight of tooth diversity in terms of compositions, structures, properties, and functions may stimulate further efforts in the synthesis of tooth-inspired materials with enhanced mechanical performance and broader property sets. The state-of-the-art syntheses of enamel mimetics and their properties are briefly covered. We envision that future development in this field will need to take the advantage of both conservation and diversity of teeth. Our own view on the opportunities and key challenges in this pathway is presented with a focus on the hierarchical and gradient structures, multifunctional design, and precise and scalable synthesis.

Reconstructing diets of hunted sika deer from Torihama Shell Midden site (ca. 6,000 years ago) by dental microwear texture analysis

Sika deer (Cervus nippon) is the most abundant ruminant in the Japanese archipelago and has been the primary hunting target, including during the prehistoric ages. Abundant skeletal remains of sika deer have been excavated from archeological sites of the Jomon periods (ca. 15,000–2,400 BP). We reconstructed the feeding habits of sika deer from the Torihama Shell Midden site in Fukui Prefecture, western Japan. The Torihama site is one of the most well-preserved archeological sites of the Jomon period, and we investigated materials from the layers of the Early Jomon period (ca. 6,000 BP). In this study, we obtained three-dimensional tooth surface texture from the lower molars of excavated deer and measured microwear texture using international surface roughness parameters (ISO 25178-2) to infer their habitat use. Next, we estimated the percentage of grasses in the diet by using the reference dataset for extant sika deer with known diets. The results show that the Torihama deer overlapped with mixed feeding and grazing sika deer populations. Moreover, the proportion of grasses in the diet was estimated to be 50.7% on average but showed a wide range among the Torihama deer. This result implied that Torihama deer were mixed feeders of dicot leaves and grasses and had a flexible diet adapted to the vegetation of its habitat. Our results support the paleoenvironmental estimation that the Torihama Shell Midden site contained mixed vegetation of evergreen, deciduous, and coniferous trees around the Mikata Five Lakes in the Early Jomon period. These findings provide insights into the highly plastic diets of the extant sika deer in the Japanese archipelago.