This review explores some ecological aspects of the common hippopotamus (hippo), Hippopotamus amphibius L, threats to its population and contextual peculiarities affecting its conservation in selected water systems in Zimbabwe. Scoping surveys of literature and thematisation of common issues related to hippo ecology, human-hippo conflict and conservation were used for data collection. Hippos play integral ecological roles, such as habitat engineering through track creation in water systems, nutrient recycling by swirl spread of highly organic faeces, harbouring commensal water birds, parasites and leeches. Regardless, the hippo population is not well documented for the country with indications of sharp declines in freshwater systems during the period 1982 to 1992 and gradual recovery thereafter. Habitat degradation, water pollution, climate change, drought-induced extreme water level fluctuation, poaching and deliberate culling, as part of problem-hippo control (PHC), are key drivers of hippo population declines. However, it appears much of the attention is on human-hippo conflict and its consequences, resulting in negative perceptions among human communities. Commercial breeding of hippos for non-consumptive tourism, and export-orientated meat, and ethnomedical mimics of hippo sweat and milk products are new, potentially viable, but unexplored options for conserving and increasing the population of the species in Zimbabwe. Currently, it appears more anti-hippo poaching patrols and awareness campaigns especially in water systems outside protected areas may be key to sustaining the current hippo population. For the future, it is essential to increase the scope for hippo census data to include water systems inside and outside protected areas for sustainable conservation of the species in the country.

Hierarchies are prevalent in social animals and display of aggression by dominant individuals often results in appetite and growth suppressions in lower-ranked fish. This study investigated the effects of dominance hierarchies on growth and some physiological responses in Nile tilapia (mass range: 120–300 g). Fish were grouped based on body mass into three classifications of one dominant and three subordinates (1D:3S), two dominants and two subordinates (2D:2S) and four equal-sized (4ES) individuals, and each grouping was triplicated. Rates of aggressive interactions under conditions of food deprivation, hypoxia and increased temperature stressors were also assessed. The 4ES treatment was characterised by more frequent aggressive interactions, compared with the other groupings. The number of lost scales recovered from the different groups after 24 h of group formations were significantly higher in the 1D:3S group. Food deprivation resulted in progressively increasing rates of aggressive interactions up to 48 h, but decreased at 72 h in all treatments. Feed intake for the 4ES group was significantly higher for than the other groups, because access to feed was largely unrestricted for all individuals. The lower-ranked individuals in the 1D:3S and 2D:2S groups had lower growth rates, compared with the dominants. Subordinate fish under treatment 1D:3S and dominant individuals in 2D:2S had elevated mean red blood cells, haemoglobin, haematocrit and white blood cell counts relative to other fish. Although aggression counts were highest in the 4ES group, the results of this study provide evidence ensuring homogeneous weights improve feed intake and growth in Nile tilapia.

The grasshopper communities of central Saharan ecosystems (Adrar region, Algeria) were studied at two scales: the first scale considered different biotopes in 23 localities. Random sampling with different traps from February 2016 to February 2019 made it possible to capture two families comprising 20 species, of which 13 are recorded for the first time in the region. The second scale concerned the desert oases. Monthly sampling from March 2017 to November 2018 captured 11 species belonging to two families and four different subfamilies. A comparative study of the grasshopper community in three palm groves with two types of habitat (cultivated and uncultivated) indicated homogeneity in fauna diversity, although their composition was very different. Phenological analysis of species in three oasis habitats revealed the presence of three groups of species: (1) a group of hygrophilic species with a reproduction period concentrated in summer, (2) xerophilic species only present during the spring and autumn, (3) a group of mesophilic species remaining present almost throughout the year and moving between the two types of habitats. Despite three years of field work with several trips and in different biotopes, we believe that the list of species presented here is not exhaustive, but only an updated list, and we consider the new data as an important resource for various future studies, especially genetic studies.

Humpback whales are known for their complex and well-structured song that is typically produced on low-latitude breeding grounds. However, there is increasing evidence of song production on migration routes and high-latitude feeding grounds. Within a breeding ground and season, males share songs that progressively change over time. Song production on migration routes leads to the cultural transmission and sharing of songs. This is the first assessment of song structure in humpback whales recorded near Cape Town, South Africa. Song was identified in recordings made between 9 September 2016 and 21 October 2016 on a moored hydrophone located in Fish Hoek, False Bay. Thirty-nine song sessions were recorded, consisting of nine distinct units, forming ten themes. Themes occasionally overlapped in time, indicating multiple simultaneous singers. They were repeated on multiple days with consistent patterns in theme transition, demonstrating song sharing amongst individuals. Convergence on a similar song structure suggests singing whales originate from the same breeding stock. We propose that an unknown proportion of these whales continue to sing beyond the recognised breeding season. These data support previous studies that found that singing is not restricted to low-latitude breeding sites.

Extended nursing periods have been observed in some pinniped species. Here, we document multiple cases of such prolonged nursing in Cape fur seals in Namibia. Over three separate visits to the Cape Cross breeding colony, we observed five unusual nursing interactions. These included animals of estimated age from one to over three years suckling on awake and permitting females. One of these observations included two individuals (juvenile and pup) suckling simultaneously. In three out of five cases, the female sniffed the large suckling animal, and the lack of aggression suggested mutual recognition. We suggest that the most likely scenario for these observations is that the larger animals might be the mothers' offspring from the previous year maintaining contact over at least three years. Such prolonged nursing may occur in cases where the year's pup is not born, dies or is outcompeted by older siblings, which can result in large energetic advantages for the offspring, by maintaining a feeding relationship with mothers over more than one year. We suggest that animals that extend suckling over more than one year may increase their overall success, although possibly inhibiting their mother's pregnancy in a given year. Under poorer conditions, investing more in an older calf may also be more cost effective to the mother than risking a new pregnancy. However, further detailed investigation is necessary to explain extended nursing in this socially complex mammal.

The diet of the marsh or water mongoose Atilax paludinosus has been well studied in coastal and inland riverine habitats, where crabs often constitute the main prey in terms of frequency of occurrence. We investigated the feeding ecology of a small number of marsh mongooses living next to a small, non-permanent reservoir (Andries Vosloo Kudu Nature Reserve, Eastern Cape), where freshwater crabs were not available. Using a combined metric of the percentage of occurrence and the percentage volume of food remains in 133 scats collected from 2006–2009, no primary prey could be detected. Amphibians, mammals, arthropods and fish all acted as secondary prey. Plants supplemented the diet, whereas birds only occurred as trace foods. There were seasonal variations in the diet, with peaks in amphibian (spring), arthropod (summer) and fish (autumn) consumption contributing to the change. Dietary diversity and niche breadth were relatively high throughout the year. This study strongly suggests that the marsh mongoose is in fact a generalist opportunist feeder. Although it consumes crabs and other aquatic prey in areas where they are particularly abundant, it can adapt to local food availability and include a significant proportion of terrestrial prey in its diet.

Elephant interaction programs, specifically ones that provide elephant back riding, have come under public scrutiny, and little information exists to show whether these activities affect animal welfare. This study examined the impact of human interactions and ride-based activities on physiological stress-related indicators in African elephants. Fifteen trained semi-captive elephants, as well as free-ranging elephants roaming under the same ecological conditions, were monitored. Faecal samples were collected over a nine-month period from both groups and these were analysed using an enzyme immunoassay detecting faecal glucocorticoid metabolites (fGCMs) with a 5β-α-ol-11-one structure. Elephants that participated in elephant-back-safari (EBS) activities showed significant decreases in fGCM concentrations when EBS were discontinued. Similarly, fGCM concentrations of the trained semi-captive individuals that did not participate in EBS showed decreased steroid concentrations over the same time. Overall, fGCM concentrations of the trained semi-captive herd and the free-ranging herd did not differ significantly. The collected data will help to better understand the physiological and behavioural requirements of semi-captive elephants with frequent exposure to humans. The findings will also help to optimise management strategies for wild elephant populations and elephants living in controlled environments on reserves exposed to wildlife tourism.

Southern Africa contains a diverse and endemic scorpion fauna, but with biological aspects remaining largely unexplored for this group. In order to gain biological insights into an understudied scorpion species, the current study investigates fine-scale spatial distributions and sexual dimorphism in the South African endemic Drab Thick-tail Scorpion (Parabuthus planicauda). The species closely track rocky areas, with the sexes homogenously distributed across habitats. Varying adult sex ratios are evident at each sampling area, likely influenced by differing vegetation cover and predation pressures. When considering size-corrected measurements, several characters are significantly sexually dimorphic in P. planicauda; this sexual dimorphism is not readily observable (<10% difference in size) based on uncorrected measurements, thereby rendering the identification of males and females in the field difficult. Even so, sexually dimorphic characters in females appear to be shaped mainly by natural selection (e.g. carapace width, pedipalp patella and metasoma), likely for enhanced feeding ability, fecundity, parental care and juvenile survival. In contrast, the male morphology may be primarily subject to sexual selection pressures on features used during courtship and mating (e.g. pectines, chela movable finger, pedipalp femur, 2nd and 4th legs). Taken together, the results reported on here add novel preliminary information on the understudied biological aspects of a South African endemic scorpion species.